(D’Eath
et al 2010). Even if chicken genotypes are selected with
sophisticated new techniques, the resulting phenotypes are
still going to have to be scrutinised for welfare in the real world. Until we have a much greater knowledge than we do
at present of all the main effects and side-effects (pleiotropisms,
linkages etc) of the genes that are being manipulated,
we will not do away with the need for classical genetics or
even traditional methods for selecting animals. On the
contrary, achieving the multiple goals for boilers will need
assessment of the phenotype in the environment in which it
will be reared and at many different stages of its life even
more urgently than ever.