Plumage condition and health of aviary-kept hens fed mash or crumbled pellets

Ln the present experiment, we evaluated the effects on plumage condition an d health of feeding a mash or a crumbled diet to two hybrids of laying hens in an aviary system. The two diets had the same composition and calculated nutrient content. A total of 3,204 birds was studied from 20 to 80 wk of a ge. Two hybrids, Lohmann Selected Leghom and SLU-1329 (two line crosses of Leghorn and Rhode Island Red), were housed in six pens each of an aviary sy stem with groups of 269 and 265 birds, respectively. There were three repli cates per treatment (diet x hybrid). Diet generally had little effect on pl umage condition, health, and tonic immobility. However, birds fed the crumb led diet had significantly fewer problems with bumble foot than those fed t he mash diet. Hybrids reacted differently in most traits studied; SLU-1329 had better health scores but more problems with cannibalism and salpingitis than Lohmann Selected Leg horns, whereas the reverse was found in the prop ortion of cases with coccidiosis. The hybrid differences found underline th e importance of genotype.