Laying depends on both temperature and hours of light-pullets-very young layers should only have no more hours of light than 12--artificial light on mature layers will cause them to lay more-but some say this forcing them to lay more--unnaturally--even to the point of shortening their life...
try Amazon for books--21st Century Poultry Breeding by Grant Brereton--referred by breeder of BLRW Foley-I understand color -but then he goes into feather patterns