I put both cocks and hens together dec/jan time but I prefer Feb to March babies as that way training in April to June ready for racing to their own loft and they get good at flying. If my old birds lay early I just put fake dummy eggs until I’m ready also same when old bird racing season starts I put some fake eggs too, to get them motavated as I like to race both cock and hens but everyone have their own views and systems.