why would you NOT want your hens laying eggs for you to eat? I don't get it.
does it help to know that i think it's after the first few hours the embryos brain is developed and after 24 the heart starts beating?
I might be wrong, but thats what I've read
letting your hens be constantly broody without the purpose of hatching chicks is cruel IMO, hens will sit and sit and sit and sit for MONTHS, waiting for those chicks to hatch, it wears them down badly.
we had a hen sit for about 7 weeks straight, when her second clutch hatched, she was SO thin, it's been almost three weeks and for a cochin she's no where near as fat as she was.
we have another hen thats been sitting for almost 5, because i wanted her to incubate some Muscovy eggs, she's getting thin too, but is still in good spirits, she's got about 9 days left on all her eggs, but the times she's done hatching out these 'scovie eggs for me, she'll also have 7 chicks due to hatch the same time, so she'll still get to be a momma.
if for whatever reason you don't want your hens laying eggs for consuption, if you've got a rooster, let them hatch babies, they won't lay whle they're broody or for the 4-8 weeks they're raising the babies.
ETA: so yes, a hen sitting on a freshly laid egg if theres a rooster, ALL of your eggs will be fertile and can grow into babies, a few hours starts the growth process but nothing that LOOKS like a chick