hatching bought eggs

I’ve got a hen hatching 6 fertilized eggs we bought and put under her while she was broody. This our first time hatching eggs and one has begun hatching. The head and most of its body have been out about 3 hours but nothing much has progressed since then. Still lying next to the mama hen with...

Aye, I've been trying to get some rarer breeds and have decided the best option is probably to hatch them in my incubator. I have some local breeders I've been communicating with but how do I know (or can I know) if they are are actually fertile and not just selling me regular store-bought eggs...

Ok, kinda long but bear with me here. I have several specific breeds I want to hatch out, but my first hatch didn’t go well 17/42 hatched, 12 survived, 6 cockerels. I added 14 more chicks (on “sale” $15ea) from the breeder and got 10 more (tiny breed, they just don’t seem to be “growing” at all)...