ozark, I just got a chicken dog myself, only from a breeder who specifically raises Pyrs for livestock guardians. We started by letting him meet some roos on a leash (puppy on the leash, not the roos), and then put him in a small pen with a few expendable roos for longer and longer times. He was being just a tad too playful with one roo, who promptly pecked him right on the head. Now he is comfortable with the chickens, although they are not comfortable with him--they keep roosting higher and higher to avoid being sniffed. He comes in the coop with me off his leash, and he always behaves; when he gets a little playful, the girls give him another peck and he calms down.
It's kinda weird, actually. He is in that horrible puppy nipping/teething stage, and he runs around nipping everything (me, DH, furniture, trees), but not the chickens. One of them got out because I hadn't firmly latched the gate the other day, he tried to round it back up into the barn. He knew that it wasn't supposed to get out.
He spends most of his day in the barn now, hanging out with the chickens, but at night he comes in the house so he won't bark.
Oh, and it's true that Pyrs have selective hearing. He can do his whole repertoire of tricks, and then 20 minutes later suddenly forget them all due to a jogger passing by.