This all sounds really weird to me. They are easy to breed, and I don't cool mine. Some of mine start wagging and scenting the second I introduce them. I wouldn't be surprised if one of your females didn't breed, but all of them, that is weird. You are getting a lot of questions that sound silly or obvious, but to be honest, I've never heard of anyone having that much trouble breeding BPs so I'm wondering the same things everyone else is asking.