HI, I've purchased a blue heeler male puppy recently and he is around 10-11 weeks. He has been really good in most things, like potty training and coming when called except when my 5 laying =hens are let out of an afternoon. He will listen to a point but still continues to chase them when I turn my back and has started to actually catch them and pin them down and give them a bit of a chew. Obviously they are not happy about this and neither am I. I end up having to chain him up so they can pick and scratch in piece around the yard. I've tried the rolled up newspaper, telling him firmly NO, and even walking him on a lead around them and when he goes to chase them I pull him up and tell him NO. It's not working which is frustrating me as he is great in all other aspects of training. Has anyone got any advice for me? I would be grateful.