|Cheng, Heng wei|
Submitted to: International Society of Applied Ethology
Publication Type: Abstract only
Publication Acceptance Date: 4/6/2005
Publication Date: 7/31/2005
Citation: Fahey, A., Cheng, H., Marchant Forde, R. 2005. Effects of chronic stress on response to social isolation in three genetic strains of leghorn hens. International Society of Applied Ethology. p. 70. Interpretive Summary:
Technical Abstract: Social stress in laying hens is a common problem affecting welfare. To address this, three genetic strains of Leghorn chickens were housed in a low (4 birds/cage) or high (10 birds/cage) density cage system at 17 weeks of age to form 6 treatments. The three genetic strains included docile (KGB), aggressive (DXL), and control (MBB) strains. Ninety-six birds (8 birds per treatment x 2 test dates) were subjected to social isolation in an opaque walled cage (120cm x 120cm) at 23wks and 27wks of age. Standing, sitting, walking, vigilance, inactivity, escapes, escape attempts, environmental pecking, head orientation, time spent in the cage periphery and time spent in the cage center were recorded during each 20-minute test period. At 30 wks of age, 12 birds per treatment were sedated and euthanized, and body weight, individual organ weight and immune function were assessed. High and low density KGB birds were found to be more vigilant than MBB (P<0.05). No other behaviors were notably affected by treatments (p>.10). High density and Low density DXL had significantly heavier body and liver weights than high and low density MMB (P<0.05). High density DXL also had greater heart weights than all other strains and densities (P<0.05). Finally, B cells, Gamma Delta cells, CD4 and CD8 cells did not appear to be affected by treatment. In conclusion, chronic social stress was shown to have little affect on ability of the three genotypes in high or low density cages to respond to social isolation or immune function. While, body and organ weights differed across genotype, there was no notable impact of stress on these parameters.