AVIARY SYSTEMS AND CONVENTIONAL CAGES FOR LAYING HENS - EFFECTS ON PRODUCTION, EGG QUALITY, HEALTH AND BIRD LOCATION IN 3 HYBRIDS

In two experiments, a total of 4346 laying hens housed in battery cage s, with three hens per cage (C), and in two aviary systems, both with tiered wire floors and litter (Lovsta with two tiers (L) and Marielund with three tiers (M)), were used for studies on production, egg quali ty, health, plumage and foot condition, bone strength and bird locatio n. Three hybrids were used: Lohmann Selected Leghorn (LSL) were kept i n all three systems, Dekalb XL (DK) were kept in both aviaries and Loh mann Brown (LB) in M only. Production and feed conversion in M were in ferior but not significantly different from C but significantly better than in L. Proportions of dirty eggs were significantly higher in the avaries. No significant differences were found in interior egg qualit y traits between keeping systems. LSL showed higher production and bet ter feed conversion than the other hybrids and a tendency for a lower proportion of mislaid eggs. Mortality varied considerably between the aviary pens, reaching 35% in LB mainly owing to cannibalism and salpin gitis. Keel bone lesions and bumble foot appeared in the aviaries, whi le toe pad hyperkeratosis was observed in C. Hens in aviaries had sign ificantly stronger bones (tibia and humerus) and showed more wounds fr om pecks, inferior plumage condition and dirtier feet than-in C. LSL h ad more bumble foot injuries than LB but better plumage condition than DK. The birds used the different parts in the aviaries well, especial ly the perches on the resting top tier during the night.