for 2 yrs running ive had 2 cocks pair together,paired them to hens early on reared young,then when on widowhood paired to each other,neither flew very well untill i seperated them into different sections then they took to hens again one tried to pair to a different cock so he is no longer here.
i also know of a fancier in the 80s who seperated his birds for 3 yrs and many cocks paired together, i had 3 cocks when he finally packed up and out of the 3 cocks 1 would never pair to a hen.
lyndon