SEARCH · PubMed Health

Results for “Broilers”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources

PubMed2005

Performance of broiler chickens given whey in the food and/or drinking water.

1. The effects on food intake and weight gain of offering broiler chickens (2 to 7 weeks of age) dry food, wet food, wet food containing whey, whey as drinking liquid and combinations of two of these were studied in 5 experiments. 2. Wet feed generally improved both weight gain and feed efficiencies significantly. Feeding whey also improved weight gain and feed conversion efficiency, but whey offered as a drinking fluid had an adverse effect on broiler performance. 3. When whey was offered both as drinking liquid and added to the food it had a deleterious effect. 4. When whey was offered from 4 or 6 weeks of age, it had a better effect than when offered from 2 weeks of age. 5. There was better performance when whey in the drinking water was diluted and/or offered on alternate days or half-days. 6. Broilers allowed to choose between wet and dry feed when water was freely available chose mostly dry feed; in the absence of drinking water they chose mostly wet food. Birds offered water and liquid whey avoided whey completely. 7. It is concluded that whey can be used in diets for broiler chickens by incorporating it in the food as long as drinking water is offered ad libitum. Whey may be offered as a drink if the food is mixed with 1.8 times its weight of water but it is better to dilute the whey with an equal volume of water whether it is added to food or given as drink. Good results can also be obtained when undiluted whey is offered alternately with water, either in half-day or full-day periods.

Aging↗

PubMed2006

Effect of formic acid on performance, digestibility, intestinal histomorphology and plasma metabolite levels of broiler chickens.

1. The effect of dietary formic acid on performance, digestibility, intestinal histomorphology and plasma metabolite levels of broiler chickens was studied. 2. An experiment with 120 Ross male broiler chickens was conducted from 1 to 42 d of age at the laboratory. There were 4 treatment groups: control (C), 10 mg/kg feed avilamycin (AV) and formic acid at two concentrations, 5 and 10 g/kg feed (FA5 and FA10, respectively). 3. No differences in weight gain, feed intake or feed conversion ratio were observed in male broiler chickens fed on the different diets. 4. An effect of the additives on ileal dry matter (DM) digestibility at 42 d of age was detected with the finisher diets; AV and 10 g/kg of feed formic acid slightly improved ileal DM digestibility compared to the other treatment groups. 5. Jejunum pH was not affected when 5 or 10 g/kg formic acid was added, and the results do not clearly show a positive effect of formic acid on the intestinal histomorphology. 6. No differences were noticed for blood metabolites in the different diets, and the levels of calcium and phosphorus in the plasma were not altered by formic acid addition. 7. In conclusion, when using broiler chickens under conditions of good hygiene, dietary formic acid did not have a clear positive effect on performance, intestinal histomorphology or plasma metabolite levels; however, there was a slight positive effect on the ileal digestibility of nutrients.

Animal Feed↗

PubMed2006

Effects of dietary metabolisable energy, calcium and phosphorus on bone mineralisation, leg weakness and performance of broiler chickens.

1. Performance, gait score (GS), tibial dyschondroplasia (TD), and tibia bone mineralisation and breaking strength were determined in 2880 male and female Ross 208 broilers fed on diets with two different concentrations of dietary metabolisable energy (ME) (11.00 or 12.00 MJ/kg) and 4 different concentrations of available phosphorus (aP) adjusted for dietary ME content (4.0, 4.5, 5.0 or 5.5 g/kg aP in starter and 3.5, 4.0, 4.5 or 5.0 g/kg aP in finisher diets containing 12.00 MJ/kg). 2. Tibia ash, calcium (Ca) and phosphorus (P) contents in broilers given diets with low ME (11.00 MJ/kg) were greater than those of broilers given diets with higher ME (12.00 MJ/kg). Tibia ash, Ca and P contents increased curvilinearly with increasing dietary aP content. The dietary aP level had no effect on GS. 3. Dietary concentration of ME or aP had no effect on tibia breaking strength. 4. Walking ability, as measured by GS, was negatively correlated with the body weight (BW) of tested birds at 23 and 35 d of age, but the dietary ME content or aP level had no significant effect on GS at 35 d of age. 5. The results indicated that bone mineral content had no clear correlation with the walking ability of broilers.

Animal Feed↗

PubMed2006

Prediction of ingredient quality and the effect of a combination of xylanase, amylase, protease and phytase in the diets of broiler chicks. 2. Energy and nutrient utilisation.

1. In order to investigate the effects of xylanase, amylase, protease and phytase in the diets of broiler chickens containing graded concentrations of metabolisable energy (ME), two 42-d experiments were conducted using a total of 2208 broiler chicks (8 treatments with 12 replicate pens in each experiment). 2. Four diets including one positive and three negative control diets were used. Three maize/soybean meal-based negative control (NC) diets were formulated to be identical in available phosphorus (P), calcium (Ca) and amino acids but NC1 contained approximately 0.17 MJ/kg less ME than NC2 and approximately 0.34 MJ/kg less ME than NC3. A positive control (PC) was fed for comparison and was formulated to be adequate in all nutrients, providing approximately 0.63 MJ/kg ME, 0.13% available P, 0.12% Ca and 1 to 2% amino acids more than NC1. 3. The reduction in nutrient density between NC1 and PC was determined using ingredient quality models Avichecktrade mark Corn and Phychecktrade mark that can predict the response to exogenous enzymes in maize/soybean meal-based broiler diets. Supplementation of each diet with or without a cocktail of xylanase, amylase, protease and phytase gave a total of 8 dietary treatments in a 4 x 2 factorial arrangement. The same treatments and diet designs were used in both experiments but conducted in different locations using different batches of maize, soybean meal and minor ingredients. 4. In both experiments, digestibility was improved by the addition of exogenous enzymes, particularly those for P, Ca and certain amino acids. In addition, the supplementation of the PC with enzymes elicited a positive response indicating that over-the-top addition of xylanase, amylase, protease and phytase may offer a nutritionally and economically viable alternative to feed cost reduction. 5. It can be concluded that the digestibility of nutrients by broilers fed on maize/soybean meal-based diets can be improved by the use of a combination of xylanase, amylase, protease and phytase.

6-Phytase↗

PubMed2006

Sunflower seed meal as a substitute for soybean meal in commercial broiler chicken diets.

1. An experiment was conducted to study the possibility of replacing soybean meal (SBM) with sunflower seed meal (SFM) in broiler chick diets. The SBM in broiler starter (317.9 g/kg) and finisher (275.4 g/kg) diets was replaced with SFM at 33, 67 and 100% on an iso-caloric and iso-nitrogenous basis using sunflower oil to balance the energy content of the diets. The metabolisable energy levels used in the diet were considerably less than the recommended levels for broilers. Each experimental diet was fed ad libitum from 2 to 42 d of age to 8 replicates of 5 birds. Parameters studied included amino acid and apparent metabolisable energy contents in food ingredients, body weight, food intake, food efficiency, leg abnormality score, dry matter digestibility, carcase traits, relative weight and length of intestine, fat and protein content in liver and serum biochemical profile. 2. SFM had higher concentrations of calcium, phosphorus, methionine and cystine and lower energy content than SBM. 3. Replacement of SBM with SFM up to 67% in starter and 100% in finisher diets did not affect weight gain. Total and 67% replacement of SBM with SFM depressed food efficiency at 21 and 42 d of age, respectively. Food intake was significantly higher in SFM-based diets than in the SBM reference diet at 21 and 42 d of age, except in groups given SFM100 at 21 d of age. In the latter group, the food intake was similar to that on the SBM reference diet. The digestibility of dry matter decreased with increased levels of SFM in the diet. 4. The relative weights of giblet, liver and abdominal fat, length of intestine, activity of alkaline phosphatase, concentrations of calcium and inorganic phosphorus in serum were not influenced by incorporation of SFM in the broiler diet. 5. The ready to cook yield and liver fat content decreased, while the relative weights of gizzard and intestine and protein content in liver increased, with increasing levels of SFM in the diet. 6. The concentration of HDL cholesterol increased while the concentration of LDL cholesterol decreased with increasing content of SFM (> or =67% of SBM) in diet. The serum protein concentration decreased progressively with increase in dietary SFM. The concentrations of protein and triglycerides in serum were lowest in groups receiving SFM100. 7. Body weight gain was not affected by total replacement of SBM with SFM at 42 d of age. However, considering food efficiency, carcase yields, serum lipid profile and level of supplemental fat in diet, it is concluded that SFM can replace up to two-thirds of soybean, corresponding to inclusion of 345 and 296 g SFM per kg for starter and finisher phases, respectively.

Animal Feed↗

PubMed1985

Effect of dietary copper on litter microbial population and broiler performance.

Proprietary broiler diets, containing added copper (125 mg/kg) as sulphate, were fed to broilers in 4 trials (32 pens each) over a one year period without a change of litter. Mould counts in the litter of pens containing birds fed the standard diets decreased to 2 X 10(3) propagules per g in trial 4. Those in the pens with birds fed the diets containing supplemental copper decreased to 6 X 10(2) propagules per g. Litter bacterial counts (10(7) organisms/g) were not affected by dietary copper. Litter copper concentrations in pens where the birds were fed supplemented diets increased significantly to more than 600 mg/kg in trial 4. Dietary copper sulphate addition significantly increased broiler weight gains at 7 weeks in trials 3 and 4 (P less than 0.05) and the efficiency of food utilisation was significantly improved in trial 4. The copper content of the chicks' livers remained unchanged. It is suggested that broiler performance may be independent of dietary copper content. Litter copper concentrations and litter microbial alterations may be important factors.

Animals↗

PubMed1986

Free-choice feeding of broilers at high temperatures.

Broilers fed complete diets to 21 but not 44 d of age grew faster with a better efficiency of food utilisation than broilers given a free-choice selection of the cereal and protein components. When finisher diets, varying in metabolisable energy (ME) and amino acid:ME ratios, were fed at high ambient temperatures (25 to 35 degrees C) broilers on the free-choice system selected similar amino acid:ME intake ratios, which were lower than the ratios contained in the complete diets. Differences in broiler performance between 22 and 44 d of age reflected variations in ME rather than amino acid intake.

Animal Nutritional Physiological Phenomena↗

PubMed1988

Influence of dietary electrolyte balance, source of added potassium and anticoccidial agents on the performance of male broilers.

1. The performance of 1680 male broiler chickens was measured from one to 42 d of age. They were given diets with three (125, 165 and 205 mEq/kg) electrolyte balances (sodium + potassium - chloride), two sources of added potassium (carbonate or sulphate) and two anticoccidial agents (90 mg/kg of either monensin or lasalocid). 2. The dietary treatments had no significant effects on the growth performance of broiler chickens in the starter phase. 3. In the finisher phase, the chickens given the diets containing lasalocid utilised food less efficiently that those given the diets containing monensin. 4. There were significant interactions between dietary electrolyte balance and source of added potassium on body weight gains and food:gain ratios in the finisher phase. In diets with an electrolyte balance of 205 mEq/kg, the inclusion of potassium sulphate instead of potassium carbonate increased body weight gains by 3.4% and reduced food:gain ratios by 4.6%. 5. The body weight gains of chickens given the finisher diets containing lasalocid and added potassium carbonate were reduced by 2.6% compared to those of chickens given the diets containing monensin or added potassium sulphate. 6. The litter moisture content was higher in pens with chickens on the diets with an electrolyte balance of 205 mEq/kg than on the diets with either 125 or 165 mEq/kg. Both lasalocid and potassium sulphate tended to increase the litter moisture content. 7. It may be concluded that the inclusion of 90 mg/kg of either monensin or lasalocid in broiler diets does not alter the balance of electrolytes required for optimum growth performance of broiler chickens.

Animals↗

PubMed1989

Effects of oxidised dietary oil and antioxidant supplementation on broiler growth and meat stability.

1. Broilers were fed on diets containing oxidised sunflower oil, sunflower oil and sunflower oil supplemented with alpha-tocopherol, butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT). 2. Oxidised oil caused a significant reduction in broiler body and carcase weights, whereas alpha-tocopherol and BHA/BHT supplementation improved growth. 3. Meat samples from these broilers were stored at 4 degrees C and -20 degrees C and their oxidative stability evaluated. Feeding oxidised oil to broilers resulted in meat that underwent rapid oxidative changes during refrigerated and frozen storage. 4. On the other hand, dietary alpha-tocopherol and BHA/BHT supplementation increased alpha-tocopherol and BHA/BHT concentrations in meat and significantly (P less than 0.05) improved the oxidative stability of meat during refrigerated and frozen storage.

Animals↗

PubMed1989

Growth, food intake and energy balance of layer and broiler chickens offered glucose in the drinking water and the effect of dietary protein content.

1. Four experiments were carried out to study the effect of offering a 91.5 g/l solution of glucose, compared to tap water, on fluid intake, food intake and growth of individually-caged immature chickens of both layer and broiler strains. 2. Male chicks of an egg-laying strain were offered glucose solution or tap water from 27 to 62 d after hatching. There was no effect of glucose on fluid intake but it depressed food intake (P less than 0.01) to give equal total energy intakes for each treatment. Body weight gain was reduced (P less than 0.001) and carcase fat content increased (P less than 0.001) by the glucose to yield no difference to total carcase energy. 3. When birds were placed in a respiration chamber for two 23-h periods there was no effect of treatment on outputs of energy as faeces + urine or as heat. 4. Male broilers were offered glucose solution or tap water with diets containing either 150 or 195 g protein/kg from 20 to 55 d after hatching. With the low-protein diet glucose depressed food intake (P less than 0.01) but total energy intake and carcase energy were not significantly affected. With the high-protein diet glucose did not depress food intake but increased total energy intake and total body fat. 5. Layer and broiler chicks were offered either a choice of the low- and high-protein diets or a single diet intermediate in protein content, with glucose solution or tap water. With broilers total food intake was depressed by glucose, mainly by a reduced intake of the low-protein diet. Intake of neither diet by the layer chicks was significantly affected by glucose. 6. It is concluded that provision of extra energy in glucose solution depresses food intake when the resultant energy:protein ratio becomes limiting. With a higher protein diet, or with birds having lower protein requirements, glucose solution does not depress food intake and increased fat deposition occurs.

Animals↗

PubMed1991

Chromosome analysis of early embryonic mortality in layer and broiler chickens.

1. Twenty-three lines of chickens, obtained from grandparent stocks of 4 Australian breeding companies, were analysed to determine the incidence of early embryonic mortality attributable to chromosome abnormalities. The lines included 10 layer strains, consisting of 6 White Leghorn, 2 New Hampshire and 2 Australorp lines, and 13 broiler lines. 2. A total of 10,730 eggs was examined after 3 d incubation; of these 9746 (90.8%) were fertile. Abortive embryonic development was observed in 1379 (14.1%) of the fertile eggs. This consisted of 952 (69.0%) dead and dying embryos, including 646 malformed and 427 (31.0%) membranes without embryos. 3. Early embryonic mortality was found to vary from 9.8 to 26.8% (average 16.4%) in broiler lines and from 8.0 to 27.9% (average 11.9%) in layer lines. 4. Among 898 abortive embryos analysed, 112 had abnormal chromosomes consisting of 27 haploids, 38 haploid-euploids, 24 triploids, 16 diploid-polyploids, 4 aneuploids, 2 tetraploids and 1 translocation. 5. In broilers and layers respectively, chromosome abnormalities were responsible for 4.4 to 28.1% (average 11.8%) and 7.4 to 25.0% (average 13.4%) of the early embryonic mortality. 6. The overall frequency of chromosome abnormalities in all fertile eggs varied from 0.7 to 3.7% for the broiler lines and 0.7 to 3.4% for the layer lines.

Animals↗

PubMed1992

Effects of different rates of drying cassava root on its toxicity to broiler chicks.

1. The effects of drying cassava root at different rates on its composition and toxicity to broiler chicks were examined. Unpeeled roots from a high-cyanide cultivar of cassava were chipped and dried at 25 degrees C to a moisture content of below 100 g/kg over 24 h for fast-dried meal (FD) or 72 h for slow-dried meal (SD). The meals were incorporated at 250 and 500 g/kg into semi-synthetic diets which were fed to day-old broiler chicks as mash or pellets in separate experiments. 2. The two drying rates produced meals with similar concentrations of polyphenols, but different concentrations of cyanogens, the latter being 38 and 482 mg total cyanide/kg for SD and FD, respectively. The linamarin, acetonecyanohydrin or total cyanide content measurements of pelleted diets were highly correlated. 3. Growth rates of chicks fed on SD-based diets were significantly higher than those of chicks fed on FD-based diets. Compared with a control diet, weight gain of chicks fed on the 500 g FD/kg diet (containing 258 mg total cyanide/kg) was 77% lower, although performance also appeared to be reduced at 142 mg total cyanide/kg. 4. The ratio of water:food intake of chicks was higher in FD than in SD groups, and this was reflected in the high water content of excreta. There was increased bile excretion, the chloretic effect increasing with the cyanogen content of diet. Pancreas weights were lower in FD than in SD groups in experiment 1 (mash diets), but not in experiment 2 (pelleted diets), while there was a significant interaction between drying method and cassava inclusion rate on liver weight in experiment 2, but not in experiment 1. There were no effects on the mortality rate. 5. Pelleting of diets generated high temperatures, but did not significantly alter the cyanogen concentration or the growth of the chicks. 6. Thus, slower rates of drying cassava roots produce meals with lower cyanogen concentration that are, consequently, less toxic to broiler chicks. Cassava root meal of less than 40 mg total cyanide/kg can be fed to broiler chicks at 500 g/kg without any adverse effects.

Animal Feed↗

PubMed1993

Incidence and classification of early embryonic mortality in broiler breeder chickens.

1. Unusually high early embryonic mortality (EEM) was observed in hatching eggs from broiler compared with white or brown table-egg breeders in Atlantic Canada. Broiler breeder EEM in Atlantic Canada was twice the EEM in broiler breeders from other areas of North America. 2. Comparisons of holding temperatures (18 and 30 degrees C) for 24 h after egg collection, in combination with a storage time of 0 or 7 d at 18 degrees C prior to incubation, were made using the criteria: embryo development (stage), and size at 0, 3, 6 and 9 d incubation, EEM, late embryonic mortality (LEM) and hatchability (HAT). 3. Stage of development of embryos, at 0 d incubation, was highest for eggs held for 24 h at 30 degrees C and stored for 7 d. Embryo stage, weight and length at 3, 6 and 9 d incubation were positively correlated. 4. Hatchability of fertile eggs was lowest (66.5%) for eggs held for 24 h at 30 degrees C and stored for 7 d and highest (87.2%) for eggs held for 24 h at 18 degrees C and stored for 0 d. Holding temperature and storage time significantly influenced EEM and LEM. 5. EEM classification differed for strain of breeder. In broiler breeders the majority of the EEM was at a relatively late stage of development (exhibiting an obvious blood ring with a visible embryo). In comparison, EEM from table egg breeders was distributed equally among three categories.

Abnormalities, Multiple↗

PubMed1993

Effect of a soluble polysaccharide (carboxy methyl cellulose) on the physico-chemical conditions in the gastrointestinal tract of broilers.

1. The effects of an indigestible soluble polysaccharide (carboxy methyl cellulose: CMC) on broiler performance (body weight gain, food and water intake) and on chyme characteristics (moisture content, viscosity, pH, osmolality and retention time) in broilers were studied. 2. In semi-synthetic diets 0, 5.0 and 10.0 g/kg of cellulose was replaced by CMC on weight basis. These diets were fed to male broilers from 3 to 5 weeks of age. 3. When 10.0 g/kg CMC was included in the diet, food intake and body weight gain were reduced, compared to the 0, and 5.0 g/kg CMC diets. Food:gain ratio and water intake were increased at each CMC concentration. The significant quadratic response showed an increased response per 5.0 g/kg dietary CMC at the higher CMC concentration. 4. The viscosity in the supernatant of the chyme was linearly increased in all intestinal segments by CMC. A quadratic increase was observed in the crop. In the lower ileum, differences between the 5.0 and 10.0 g/kg CMC diets were not significant. 5. CMC increased the mean retention time of chromium in the duodenum and in the upper jejunum, and reduced the maximal rate of marker excretion. The transit time (first appearance of the marker in the excreta), however, was significantly reduced at the highest CMC concentration. 6. The osmolality of the intestinal fluid decreased less as the chyme moved from the duodenum into the lower ileum, with increasing concentrations of CMC. 7. The ileal pH was reduced linearly by the CMC content of the diet. 8. Based on a higher moisture content of the chyme in the CMC-fed birds, and the higher jejunal and ileal osmolarities in those birds, it was concluded that the efficiency of both digestion and absorption was reduced by CMC inclusion in broiler diets.

Animals↗

PubMed1994

Energy and nitrogen metabolism and oxygen use by broilers susceptible to ascites and grown at three environmental temperatures.

1. An experiment using respiration calorimetry was performed to examine the energy and nitrogen metabolism of 2 strains of male broilers grown at 3 environmental temperatures; the results were then related to the susceptibility of the strains to the ascites syndrome. 2. Broilers selected for food conversion efficiency were less responsive to environmental temperature than were broilers selected principally for increased weight gain. 3. The susceptibility to ascites of broilers selected for food conversion efficiency may be the result not of a genetic incapacity to use oxygen but of the ability of the bird to maintain growth rate in adverse thermal environments.

Animals↗

PubMed1994

Response of broiler chicks to threonine-supplemented diets to 4 weeks of age.

1. Two experiments were carried out to determine the response of broiler chicks to threonine-supplemented diets between 10 and 28 d and 7 and 21 d of age, respectively. 2. In the first experiment female broiler chicks were fed on 11 experimental diets. Two iso-energetic basal diets (diets 1 and 2) were prepared with 200 and 160 g CP/kg and 7.6 and 6.0 g threonine/kg respectively. Both diets contained 11.5 g lysine and 8.7 g sulphur-containing amino acids/kg. Diet 3 was composed of diet 2, supplemented with all essential and non-essential amino acids (EAA and NEAA, respectively) except threonine, to the concentrations of the amino acids in diet 1. The NEAA were added as a combination of glutamic acid and glycine. Diets 4 to 11 had the same compositions as diet 3, but contained increasing amounts of threonine. 3. For birds fed on diet 2, gain was significantly lower and food/gain ratio was significantly higher than for birds fed on diet 1. Supplementation with EAA, NEAA and threonine to the same concentrations in diet 1 resulted in a performance similar to that found on diet 1. 4. In experiment 2, male and female broiler chicks both received 10 experimental diets. Diet 1 contained 220 g CP/kg and 8.5 g threonine/kg, diet 2 contained 160 g CP/kg from natural raw materials and 6 g threonine/kg. Both diets contained 12.4 g lysine and 9.3 g sulphur-containing amino acids/kg. Basal diet 2 was supplemented with all EAA and NEAA to the concentrations of basal diet 1, except for threonine. Diets 3 to 10 had the same compositions as the supplemented diet 2, but contained increasing amounts of threonine. 5. For male and female chicks on diet 2, gain was significantly lower and food/gain ratio significantly higher than those on diet 1. Diet 10 (160 g CP/kg plus all EAA, including threonine, and NEAA supplemented to the concentrations of diet 1) resulted in the same performance as diet 1. 6. The results indicate that, when low protein maize-soyabean meal diets supplemented with EAA and NEAA with 13.31 MJ ME/kg were fed to male and female broiler chicks until 21 d of age, improvements in gain and food/gain ratio were obtained when the dietary threonine content was increased to 7.25 g/kg. When female chicks were fed threonine-supplemented diets to 28 d of age, improvement in gain and food/gain ratio was obtained when the threonine concentrations were increased to 6.32 g/kg diet.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of Variance↗

PubMed1994

Effects of dietary mineral supplementation on the performance and mineral retentions of broilers at high ambient temperatures.

1. The relationship between broiler performance and two dietary mineral balance equations was investigated at a high constant ambient temperature (30 degrees C) using a range of 11 salt supplements given to male broiler chicks from 21 to 42 d of age. 2. No relationship was found between broiler performance and either of the two balance equations. 3. Re-evaluating these equations using retained, rather than dietary, mineral concentrations did not improve the relationship although changes in mineral retentions associated with the supplements indicated that dietary concentrations were not a good indicator of the impact of the diet on the bird's acid-base homoeostasis. 4. Evidence was found that metabolisable anions supplemented in association with mineral cations may have a significant effect on broiler performance.

Animal Feed↗

PubMed1996

Vertical temperature profiles at bird level in broiler houses.

1. The temperature in the close vicinity of commercial broilers was studied in relation to the setpoint temperature throughout the rearing period. 2. Mean temperature in the immediate environment of the chicks was 2.0 degrees C lower than the setpoint of 1 d of age. During the first week this initial temperature difference gradually rose to l.7 degrees C above setpoint. At 18 d of age a further rise to a mean difference of 4.0 degrees C above setpoint was measured. The difference then remained constant from 32 d of age until the end of the fattening period. 3. It was concluded that the chickens were actually brooded at 30 degrees C. During the rearing period the ambient temperature in the close vicinity of the broilers gradually declined to 26 degrees C. 4. During the finishing period, ambient temperature around the broilers was far above the value recommended for optimal food intake and growth. 5. These results are discussed in relation to heat generation and heat fluxes in the broiler houses.

Aging↗