Effects of perches on foot lesions and behaviour of individually caged broiler breeder cocks

Twelve 22 weeks old White Cornish cocks that had been reared on the litter floor were divided into 3 groups; conventional cages without perches (C); cages with perches in C (P); cages with perches spaced 1.7 times larger than C (PW) and kept in individual cages for 36 weeks (57 weeks old). C and P cages were 605 mm wide, high and deep. PW cages were 605 mm wide, 705 mm high and 905 mm deep. All cages floor were made of mesh wire 60.5 x 67.2 mm x 3 mm in diameter. The perches were installed 70 mm above the cage floor, in the center of the cage (P) and 600 mm from the cage from (PW). The initial average weight of birds was 3534g. The behaviour, utilization of perch and incidence of foot lesion of birds were compared among treatments. Relationships of foot lesion to behaviour and utilization of perch were also examined. Foot lesion appeared in all treatments and got worse with prolonged confinement in cage and the C and P were worse than PW treatment. The utilization of perch in PW birds was significantly higher than that in P birds where the comb touched the cage roof at age 25 weeks. Foot lesion at age 57 weeks in P and PW had significant negative correlation with the utilization of perch and sternum-lying behaviour on the perch at age 25 weeks. In addition, sham-ingestion, resting and grooming behaviours, which should be conflict behaviours, appeared to develop due to a new environment just after the transfer, and some of them were kept three weeks longer. The present results suggested that foot lesion of broiler breeder cocks would be suppressed by the utilization of perch and sternum-lying behavior on the perch for about 3 weeks in individual cages. Moreover, in the cage with perch, conflict behaviours (sham-ingestion and standing) decreased and, on the other hand, comfort behaviours (sternum-lying and grooming) increased, suggesting that perches could reduce stress due to confinement in cage