title: Effects of stock density on the laying performance, blood parameter, corticosterone, litter quality, gas emission and bone mineral density of laying hens in floor pens.
abstract: The effects of stocking density on the performance, egg quality, leukocyte concentration, blood biochemistry, corticosterone levels, bone mineral density, and noxious gas emission of laying hens were investigated. Eight hundred 34-week-old Hy-Line Brown laying hens (Gallus gallus domesticus) were randomly assigned to one of 4 treatments, each of which was replicated 4 times. Four stocking densities, including 5, 6, 7, and 10 birds/m2, were compared. A commercial-type basal diet was formulated to meet or exceed nutrient recommendations for laying hens from the National Research Council. The diet was fed to the hens ad libitum for 8 wk. Results indicated that hen-day egg production, egg mass, and feed intake were less for (P < 0.01) 10 birds/m2stock density than other stock densities. Production rate of floor and broken eggs and eggshell strength were greater (P < 0.01) for 10 birds/m2stock density than other stock densities. There were no significant differences in the level of leukocytes among densities. However, heterophils and the H/L ratio were greater (P < 0.01) for 10 birds/m2than in stock density of 6 or 7 birds/m2Serum corticosterone was greater (P < 0.01) 10 birds/m2than stock density than other stock densities. Litter moisture and gas emission (CO2and NH3) were greater (P < 0.01) for 10 birds/m2than stock density than 6 and 7 birds/m2stock density. Bone mineral content was not influenced by increasing stock density. However, bone mineral density was less (P < 0.05) for 10 m2stock density than other stock densities. These results indicate that increasing the density beyond 5 birds/m2elicits some negative effects on laying performance of Hy-Line brown laying hens.
authors: Poultry Science Division, National Institute of Animal Science, RDA, Cheonan-si, Chungnam 331-801, Republic of Korea.
authors: H K
authors: HK
authors: Kang
authors: Poultry Science Division, National Institute of Animal Science, RDA, Cheonan-si, Chungnam 331-801, Republic of Korea.
authors: S B
authors: SB
authors: Park
authors: Poultry Science Division, National Institute of Animal Science, RDA, Cheonan-si, Chungnam 331-801, Republic of Korea.
authors: S H
authors: SH
authors: Kim
authors: Poultry Science Division, National Institute of Animal Science, RDA, Cheonan-si, Chungnam 331-801, Republic of Korea kch8059@korea.kr.
authors: C H
authors: CH
authors: Kim
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000822:Animal Husbandry; D000818:Animals; D015519:Bone Density; D002245:Carbon Dioxide / Q000378:metabolism; D002645:Chickens / Q000097:blood / Q000502:physiology*; D003345:Corticosterone / Q000097:blood*; D004032:Diet / Q000662:veterinary; D004435:Eating / Q000502:physiology; D004531:Eggs / Q000592:standards; D005260:Female; D006799:Housing, Animal; D010058:Oviposition / Q000502:physiology*; D011153:Population
chemical_list: D002245:Carbon Dioxide; D000641:Ammonia; D003345:Corticosterone
keywords: Hy-line Brown laying hens; animal welfare; bone mineral density; corticosterone; laying performance; stock density