I ordered some roosters so that I can have some chicks next spring. Right now I have 12 pullets. 8 of them are Ameraucanas and 4 are Rhode Island Reds. I ordered 3 Ameraucana roosters and 7 Buff Orpington roosters. 2 of the Ameraucana chicks were dead on arrival, so I am left with only 1 Ameraucana rooster for breeding. I don't mind breeding the Rhodes with a Buff next spring. However, I want to keep the Ameraucanas pure. My question is this -- How far in advance of keeping the eggs for hatching do I need to isolate the breeder hens from the rest of the flock to ensure pure Ameraucanas. Or should I isolate the Buff Orpington Rooster from the rest of the flock and then reintroduce him to the 4 Rhodes. I know that I will have to isolate the Ameraucana breeders when I get ready to save the eggs for hatching. Another question, How many hens should I save eggs from to be able to hatch out around 20 or so eggs?