We have them seperated. And the dog isn't allowed in the chicken area. Ever. I watched my dog as I raised my chicks. She knew the rules while they were in the brooder. When they went outside, she didn't pay any attention to them. Knowing she's a prey driven dog, I had her with me, away from the chickens and watched. She would just stare at them, then all of a sudden it was like a switch was flipped and her brain said, "CHICKENS! Those things are CHICKENS!!!!! I want those CHICKENS!" I knew it would happen, so was prepared. (And the chickens were fenced off.) But it doesn't matter how well a dog is trained. They are what they are. I agree. Keep them separated. Eventhough mine didn't have the symptoms of cocci, I'm very grateful to the vet for suggesting the test. It was enough for me to keep her away. And I was lucky enough to get her treated.