What a cute dog! Looks like he'll be a nice blue for you!
We have a heeler, and they are definitely not chicken killers in my experience. Raise him around chickens and he'll be thinking they are HIS! LOL Ours is very protective of the flock, and always keeping an eye on them. If he hears squawking, he goes a running to the barn! A few times we had visitors bring their dogs and our guy gave them the evil stare every time the other dogs got too close to HIS animals.
Good luck and make sure you socialize, socialize, socialize! Heelers are definitely a one person dog and they can be a bit "growly" at strangers. We usually have to put ours in the garage if we know we're having company.