Do hens know if an egg is fertile?

[chickenboy121]

I have one hen that's like the mama bird to all the eggs , but she has never really sat on any until now. She's been sitting on some eggs for about 16 days now and I think it would be a waste to wait 21 days and have nothing happen.Can she tell if they're fertile?(I don't even think half of them are hers)And if they are fertile, when do I take them out so other chickens don't get the hatchlings? Thank you

 

[Barred4Life]

My hen covered a bunch of eggs that weren't hers...some fertile, some not. The fertile ones hatched and she stayed on the nest for the infertile ones. Do I think the hens can tell if the egg is fertile? Nope! I had to take the infertiles out so she would get off the nest and start teaching her chicks the chicken ways.

She was a bantam hen raising Barred Rock chicks...so cute, they grew up too big for her in no time, haha.
As for the other birds...I separated them prior to the chicks hatching. Once born I though...hum I wonder if they would get along with the others. BIG mistake, the hen was really in 'mother hen' mode and tried fighting another hen in a crazy battle (never had seen that!). Caught the one I introduced and separated them until they were around 10 weeks old. I know these bantams are high strung, so maybe not all birds would react the same way, but I wouldn't recommend it. Separate mama and her eggs from other birds prior to hatching.

 

[chickenboy121]

Ok thanks!Thats funny my hen is a bantam,too!And my Barred Rock hens showed signs of mating!