Chicken Eggs for Hatching

We ordered some fertilized eggs off Ebay. We have 7 Welsummer and 7 Barred Rock. We hope to have mostly (all would be great) hens. We picked up 2 barred rocks a week ago. They are supposed to be 12-14 week old Barred Rock (BR) hens. One may be a rooster (lighter and larger than the other). Hens are supposed to be darker. The darker one seems to be smaller than I'd imagined. I hope it's not a bantam barred rock. They won't begin to lay until about 18 weeks of age. Our hope is for them to breed with Able, our Rhode Island Red rooster that we picked up a week ago. If successful, we will have Barred Rock roosters (male chicks) and Black Stars (female chicks). They call them sex-links because you can determine their sex by their color. We hope to incubate the eggs today once the temperature gets about 95 degrees in the incubator. Two of the eggs (one of each) we will let Pearl (Sussex hen) incubate. She is very broody. I placed one BR egg under her a little while ago and it seems she does not mind that it's not her egg. In a little while, I will add a Welsummer egg to Pearl's nest. We hope she'll hatch the eggs and raise the chicks as hers. If so, we may keep her as our brood hen. I'd love to have a couple of Buff Orpingtons for that job. We should expect to have chicks in 21 days. That would be June 9th. We'll let you know how it goes