Use of aerial perches and perches on aviary tiers by broiler breeders

摘要

Perching, especially during the night, is an innate behaviour of chickens and the provision of perches is mandatory for laying hens in multiple countries. We examined whether broiler breeders of the fast (Ross 308) and relatively slow (Sasso) growing hybrids used aerial perches (P) and perches on aviary tiers (A) during rearing and production and how it affected welfare and production in comparison to controls without perches. Two hybrids and three treatments (control, aviary, perch) were employed in a cross-factorial arrangement. Control pens consisted of litter, raised slats, group nests, two feeder and one drinker lines. Perch-pens (P) included eight wooden perches in an A-frame configuration at 25, 50, 75, 100 cm above the slats and aviary-pens (A) included four aviary tiers with wooden bars and perches arranged as a platform (70 x 450 cm) at 55,68,115, and 138 cm above the slats. Each treatment combination was replicated three times resulting in a total of 18 pens. Welfare parameters of hens were assessed at 45 weeks and production was monitored continuously. Both hybrids used perches increasingly with age and predominantly at night (both tests P & 0.0001). Birds in control pens perched on the grill above the feeders and drinking lines more than birds in A or P (P = 0.0002) and perches were more used in A than P pens (P = 0.002). More brood eggs were collected in control pens than in the other treatments (P = 0.02) and A-pens yielded more floor eggs (P = 0.007) than control pens and P-pens. Keel bone fractures were less frequent than in laying hens but hens in A and P pens had more keel bone fractures than hens in control pens (P = 0.02) and Sasso had more than Ross (P = 0.002). In conclusion, our results suggest that broiler breeders are highly motivated to access aerial perches or perches on aviary tiers similar to laying hens with a similar welfare problem of keel bone fractures. Perches had no influence on hatching rates but measures should be taken against floor eggs to avoid a loss of brood eggs.