RIR-YELLOWLEGS
Songster
you are 100% right and what you have done is one of the very best way for breeding the desired stock.I put the hens I want to breed in a separate pen with a nest box for several weeks..easy enough to check eggs for the fertile ring.. when no more fertile then I add the desired cock for a week and don't incubate ANY until I consistently get fertile rings again.
Only other way is to pen all except the desired cockerel away from rest of flock and wait a month.