My old German Shepherd loved to watch over our chickens. When they would wander to close to the neighbors or the woods, he would round them up and bring them back in the yard. His only fault was that when I had chicks, he would wait until they were about 3 weeks old (just plump enough) and wait until I left. Then he would break into the pen I had them in and go on a killing spree. He never messed with chickens of any other age. The GS dog I have now is not so good with chickens. I tried holding them in front of them last year from the time we got them and letting him see them and smell them and then I would say "Mine." He really acted like he knew what I meant and would watch them all the time but seemed to leave them alone for the first 6-7 months. Then I found 2 chickens dead in the yard a few months ago and think that he was probably the culprit.