if you start your youngbirds at a low milage (like at 1 or 2 miles they will going reaking and you don't want that you want them to come straight home and go in the loft.
if i was you i would set a limit of how many youngbirds you are going to breed and stick to it. Then make the old birds sections smaller so that you are on top the birds.
you see pigeons do not like the cold weather specially when they are in the moult around neck so i would stop them straight away and let them get a good moult. Then bring them out as yearlings