Test station for egg layers 1978-80 [hens, pullets, broiler parent stock, commercial egg production, White Leghorn, White Plymouth Rock, feed conversion, feed consumption, health, mortality, rearing, specific gravity]

During the period of the trial 1978/80, 28 groups of egg layers each consisting of 60 pullets and 14 groups of broiler parent stock each consisting of 50 pullets were tested at "Favrholm" where the stock was also reared. 8 groups out of the 28 groups of egg layers were of the commercial egg production stock; these birds were also hatched at "Favrholm". The 20 groups of the egg layers and all groups of the broiler parent stock were experiment groups and were White Leghorn (WL) and White Plymouth Rock (WPR) respectively. The average weight of 20-week-old commercial layers was 1.60 kg and the consumption of feed was 8.93 kg. The corresponding figures for the White Leghorn were 1.31 kg and 8.05 kg, and for the White Plymouth Rock 2.24 kg and 10.92 kg. During the 448-day-testing period the average hen-day yield of the commercial egg production stock was 315 eggs or 19.3 kg egg mass. The feed conversion was 2.86 kg per kg egg. The corresponding figure for the White Leghorn was 324 eggs or 19.4 kg egg mass and the feed conversion was 2.65 kg per kg egg. The broiler parent stock was controlled over 280 days; the yield was 147 eggs, average of 64.9 g in weight, and the feed conversion was 5.17 kg per kg egg (337 g per egg). The health of the stock was good. Exclusive of the first week mortality, only 0.9 per cent of the chickens from the commercial laying section, 0.8 per cent of the White Leghorn, and 2.8 per cent of those from the broiler parent section died during the rearing period (20 weeks). In the 64 -week-laying period the mortality was 7.52 per cent and 6.51 per cent for the commercial layers and the White Leghorn respectively. In the 40-week-laying period 5.14 per cent of the broiler parent stock died. When the hens in the egg layer section were 427, 504, 565, and 566 days of age, the daily egg production was collected for measurements of the specific gravity. Specific gravity determined by the floating procedure was 1.079, 1.078, 1.076, and 1.075 respectively.