Hi, Hillbilly! Welcome to BYC!! The first problem you have is that heelers are bred to ..... well, heel. He is doing what his instincts tell him. The second problem is that he is a puppy. Puppies love to play and chase and chew and pounce - all games that are not fun for chickens. The only thing you can do is train him to ignore his impulses and maybe you won't lose any, but I would never trust him alone with the birds, at least not until he is at least three or four or older.
The first thing you must do is teach him some basic obedience (commands) and make sure he gets plenty of exercise. If he has a job to do, it will make him a happier and more compliant pup. Next, make sure he knows that he is not to play with the birds, EVER, and prevent it from happening for as long as you can. He should not bark at, chase, follow, whine for, or even LOOK at them with excitement. They are not his birds, they are your birds and he is not to even think about them, or he will have to face your disapproval.
Watch his ears and body language. As soon as you see him look alert (fixed stare, ears piqued, tensed muscles) correct him. If you have to, stand between him and the birds and make him look at you. Don't stop your claim until he backs off and looks away.
Even with all of this, it may still be too hard for him to resist "playing" with them if any opportunity arises, and it will mean dead birds. I have lost more birds (probably a hundred or more) to my own dogs than to all the wild predators combined. It is hard to overcome instincts, but there are lots of dogs that are good with birds in spite of that. My lab was the most obedient, loving, loyal dog I have ever had. I had o doubt that once he understood that I didn't want him to bother them, he would be fine, and he was, for two years. Then one day, I came home to two dozen dead birds strewn around the yard. It took two more times for me to believe that he was doing it although all evidence pointed to him. He was a chicken killer. I tried and tried but I could not train him out of it. As long as I was outside, he would not even look at them. They would fly into his pen, walk under his belly, and eat with him out of his bowl. But if I was not around, he would kill them. He just couldn't help himself. We live way out in the country and my chickens free range all day and are locked up at night. I ended up keeping him in a large outdoor kennel during the day, if I was at work or away, and letting him out at night. He did a good job of keeping predators away at night but would try all the coop doors just in case I had left one unsecured.
The main thing is to train your pup to mind you so that you can control him, then don't leave him alone with them until he is much older and has been trustworthy for a long time.
Thanks for the advice. I came home today and my bulldog had killed one of my barred rock pullets. He is always calm around them and has never been rough with them and the pullet didnt have puncher wounds so he probably stepped on her. But he is what i have been using to train my heeler to mind
Chickens are dinner, and toys, and entertainment, to any carnivore. Training will take a lot of time and effort, and may be totally successful, or not. Right now I own two terriers (terrors?) who love chicken, so they have their Ft. Knox yard, and the chickens just don't go there. Definitely not twice! I don't have the energy/ patience/ bloody minded determination to convince these lovely dogs to NOT hurt the birds, so separation is the answer here. My previous retrievers and a pointer were here from babyhood, and trained easily. Your Heeler will want to herd them, and that's tricky behavior to modify. Better than terriers, though. Mary