I have owned two Pyrs and not as LGD's. But I don't know of anyone who has or had them to gaurd chickens. Only livestock, like sheep and goats. Most dogs will kill things that run. Some dogs will kill cats that aren't cats that they consider theirs. My female Pyr herds my cats and other 2 dogs one who is a Pyr/Lab mix and a big wuss. Most Goldens and a lot of Pyrs won't kill small animals or chickens but if it runs good chance they will chase unless trained very well and consistently. My 5 yr old retriever would snatch birds out of the sky when under 2 yrs old no matter how much training or how much in trouble he was afterward. He is better now and can listen and follow commands better period. He's a bit on the crazy side but they all have the potential depending on their personality.