I recently decided to keep a hen only flock because I have young children and I can't trust my roosters. But I would like to hatch eggs before I cull. So how old should my hens and roo be to get a good hatch.
Most do not like hatching pullet eggs because of their relatively small size and limited 'nutrients' for the growing chicks. Once the eggs increase in size you can start hatching them. Once the cockerels/roosters start breeding the hens, the eggs will be fertile regardless of the age of the male.
I agree, as long as the cockerel is mating the hen, those eggs are likely fertile. With a mature hen you should be good to go. folks do hatch pullet eggs, but I think the success rate can be pretty dismal and why deal with dead chicks?