caa a22 4500 397567324 CHVBK 20180308164831.0 cr unu---uuuuu 161202e199604 xx s 000 0 eng 10.3382/ps.0750447 doi (NATIONALLICENCE)oxford-10.3382/ps.0750447 MUIR W. M. Department of Animal Sciences, Purdue University, West Lafayette, Indiana 47907 Group Selection for Adaptation to Multiple-Hen Cages: Selection Program and Direct Responses [Elektronische Daten] [W. M. MUIR] A selection experiment was initiated with a synthetic line of White Leghorns in 1982 to improve adaptability and well-being of layers in large multiple-bird cages by use of a selection procedure termed "group selection”. With this procedure, each sire family was housed as a group in a multiple-bird cage and selected or rejected as a group. An unselected control, with approximately the same number of breeders as the selected line, was maintained for comparison and housed in one-bird cages. Annual percentage mortality of the selected line in multiple-bird cages decreased from 68% in Generation (G)2 to 8.8% in G6. Percentage mortality in G6 of the selected line in multiple-bird cages was similar to that of the unselected control in one-bird cages (9.1%). Annual days survival improved from 169 to 348 d, eggs per hen per day (EHD) from 52 to 68%, eggs per hen housed from 91 to 237 eggs, and egg mass (EM) from 5.1 to 13.4 kg, whereas annual egg weight remained unchanged. The dramatic improvement in livability demonstrates that adaptability and well-being of these birds were improved by group selection. The similar survival of the selected line in multiple-bird cages and the control in one-bird cages suggests that beak-trimming of the selected line would not further reduce mortalities, which implies that group selection may have eliminated the need to beak-trim. Corresponding improvements in EHD and EM demonstrate that such changes can also be profitable. The most surprising finding was the rate at which such improvement took place, with the majority of change in survival occurring by the third generation. However, EHD continued to improve at the rate of 4% per generation. © 1996 Poultry Science Association, Inc. Breeding and Genetics nationallicence group selection nationallicence well-being nationallicence beak-trimming nationallicence layer nationallicence cannibalism nationallicence Poultry Science Oxford University Press 75/4(1996-04), 447-458 0032-5791 75:4<447 1996 75 ps https://doi.org/10.3382/ps.0750447 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.3382/ps.0750447 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- MUIR W. M. Department of Animal Sciences, Purdue University, West Lafayette, Indiana 47907 NATIONALLICENCE 773 0- Poultry Science Oxford University Press 75/4(1996-04), 447-458 0032-5791 75:4<447 1996 75 ps Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford