I have 10 hens and 1 rooster. I am thinking of next spring, I know that my chickens will be able to raise their own chicks, and I have a plan for any roosters that hatches. I am worried about how many chicks we may get this is my very first flock and I don't know what to expect for the number of chicks that could hatch. Also there are other breeds of chickens I would like to get so I was thinking of buying fertilized eggs to put under my hens when they go broody, 7 of them are 10 months old. Is there any problem adding bought fertilized eggs into a nest that already has a broody with eggs?