Need help on dog training, need really dog trainers!?

I'm a trainer for Petco too. Have you got a mentor in your store or district that you can call and ask for advice? Kelpies are herders so it could be that he's just "herding" his family, stress, or aggression. In any case, it sounds like you're uncomfortable working with this dog and his family because of the biting and the owner hitting him. Talk to your manager and tell him/her what's going on and suggest a dog behaviorist. If this dog has bitten you, it's probably time to send him to someone that can figure out why he's biting and then work from there.