Short-latency stressor effects on sociality in broiler chicks known to show contrasting T-maze behavior.

MARIN R. H.; JONES, R. B.; FREYTES P,

Atlanta, Georgia, Estados Unidos

Congreso; International Poultry Scientific Forum.; 2000

Poultry Science Association

Ninety six newly hatched broiler (Cobb) chicks were socially housed in 8 mixed-sex groups, each comprising 12 birds. The times taken by individually-tested chicks to traverse a T-maze and thereby reinstate visual contact with their companions were measured at 2 days of age. Chicks were assigned to high (HP) or low (LP) performance categories according to whether they completed this task quickly (< 25s) or more slowly (> 75s), respectively. These chicks were then marked to facilitate later identification before their return to the home cage. Sociality was measured at 9 or 10 days of age by placing chicks individually in a start box at one end of a 2-m long runway; a goal box at the opposite end contained two other chicks. Forty four chicks were tested following one of two treatments. Control chicks (11 HP, 11 LP) remained undisturbed in the brooder until testing whereas stressed birds (11HP, 11 LP) were subjected to mechanical restraint for 5 min one hour before test. At test, we measured the latencies to leave the start box and to enter a close zone (20 cm section nearest the goal box) as well as the accumulated time spent in the close zone during the 10 min test. A two-way analysis of variance (treatment, chick category) revealed no detectable effects on either of the latency measures, probably because running times were very low. However, HP chicks spent longer (F1,40 = 4.11, P<0.049) in the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. later identification before their return to the home cage. Sociality was measured at 9 or 10 days of age by placing chicks individually in a start box at one end of a 2-m long runway; a goal box at the opposite end contained two other chicks. Forty four chicks were tested following one of two treatments. Control chicks (11 HP, 11 LP) remained undisturbed in the brooder until testing whereas stressed birds (11HP, 11 LP) were subjected to mechanical restraint for 5 min one hour before test. At test, we measured the latencies to leave the start box and to enter a close zone (20 cm section nearest the goal box) as well as the accumulated time spent in the close zone during the 10 min test. A two-way analysis of variance (treatment, chick category) revealed no detectable effects on either of the latency measures, probably because running times were very low. However, HP chicks spent longer (F1,40 = 4.11, P<0.049) in the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. slowly (> 75s), respectively. These chicks were then marked to facilitate later identification before their return to the home cage. Sociality was measured at 9 or 10 days of age by placing chicks individually in a start box at one end of a 2-m long runway; a goal box at the opposite end contained two other chicks. Forty four chicks were tested following one of two treatments. Control chicks (11 HP, 11 LP) remained undisturbed in the brooder until testing whereas stressed birds (11HP, 11 LP) were subjected to mechanical restraint for 5 min one hour before test. At test, we measured the latencies to leave the start box and to enter a close zone (20 cm section nearest the goal box) as well as the accumulated time spent in the close zone during the 10 min test. A two-way analysis of variance (treatment, chick category) revealed no detectable effects on either of the latency measures, probably because running times were very low. However, HP chicks spent longer (F1,40 = 4.11, P<0.049) in the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. later identification before their return to the home cage. Sociality was measured at 9 or 10 days of age by placing chicks individually in a start box at one end of a 2-m long runway; a goal box at the opposite end contained two other chicks. Forty four chicks were tested following one of two treatments. Control chicks (11 HP, 11 LP) remained undisturbed in the brooder until testing whereas stressed birds (11HP, 11 LP) were subjected to mechanical restraint for 5 min one hour before test. At test, we measured the latencies to leave the start box and to enter a close zone (20 cm section nearest the goal box) as well as the accumulated time spent in the close zone during the 10 min test. A two-way analysis of variance (treatment, chick category) revealed no detectable effects on either of the latency measures, probably because running times were very low. However, HP chicks spent longer (F1,40 = 4.11, P<0.049) in the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. < 25s) or more slowly (> 75s), respectively. These chicks were then marked to facilitate later identification before their return to the home cage. Sociality was measured at 9 or 10 days of age by placing chicks individually in a start box at one end of a 2-m long runway; a goal box at the opposite end contained two other chicks. Forty four chicks were tested following one of two treatments. Control chicks (11 HP, 11 LP) remained undisturbed in the brooder until testing whereas stressed birds (11HP, 11 LP) were subjected to mechanical restraint for 5 min one hour before test. At test, we measured the latencies to leave the start box and to enter a close zone (20 cm section nearest the goal box) as well as the accumulated time spent in the close zone during the 10 min test. A two-way analysis of variance (treatment, chick category) revealed no detectable effects on either of the latency measures, probably because running times were very low. However, HP chicks spent longer (F1,40 = 4.11, P<0.049) in the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. later identification before their return to the home cage. Sociality was measured at 9 or 10 days of age by placing chicks individually in a start box at one end of a 2-m long runway; a goal box at the opposite end contained two other chicks. Forty four chicks were tested following one of two treatments. Control chicks (11 HP, 11 LP) remained undisturbed in the brooder until testing whereas stressed birds (11HP, 11 LP) were subjected to mechanical restraint for 5 min one hour before test. At test, we measured the latencies to leave the start box and to enter a close zone (20 cm section nearest the goal box) as well as the accumulated time spent in the close zone during the 10 min test. A two-way analysis of variance (treatment, chick category) revealed no detectable effects on either of the latency measures, probably because running times were very low. However, HP chicks spent longer (F1,40 = 4.11, P<0.049) in the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. > 75s), respectively. These chicks were then marked to facilitate later identification before their return to the home cage. Sociality was measured at 9 or 10 days of age by placing chicks individually in a start box at one end of a 2-m long runway; a goal box at the opposite end contained two other chicks. Forty four chicks were tested following one of two treatments. Control chicks (11 HP, 11 LP) remained undisturbed in the brooder until testing whereas stressed birds (11HP, 11 LP) were subjected to mechanical restraint for 5 min one hour before test. At test, we measured the latencies to leave the start box and to enter a close zone (20 cm section nearest the goal box) as well as the accumulated time spent in the close zone during the 10 min test. A two-way analysis of variance (treatment, chick category) revealed no detectable effects on either of the latency measures, probably because running times were very low. However, HP chicks spent longer (F1,40 = 4.11, P<0.049) in the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. <0.049) in the close zone than LP ones and this social reinstatement behavior was markedly greater (F1,40 = 10.79, P<0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. <0.002) in the stressed birds than in controls. There were no significant interactions. The present results support our previous suggestion that underlying sociality (motivation to be near conspecifics) is greater in HP than in LP chicks. They also clearly demonstrate that the imposition of a known stressor increased sociality in chicks of both categories. Key Words: Broiler chicks, Sociality, Stress, T-maze behavior: Broiler chicks, Sociality, Stress, T-maze behavior