Hi DaeDreamer,   I am glad

Chris Chuck
Hi DaeDreamer,
I am glad you adopted a pit-lab. With some attention she will make a great pet. Keep in mind that any dog can be food and treat aggressive, not just dogs that are part or pure pit bull.It sounds as if you have two alpha dogs that are fighting to be the pack leader. They will begin doing this early. Just remember that you and your family are number one and the dogs are number two together.
It sounds as if your initial reaction to the situation was the right one. I have a few more steps that might be useful as well. My dog, even though very submissive, has had the same problem with guarding her treats even growling and nipping at alpha dogs. Early on, she even growled at my kids and me when she had a treat; however, we quickly put an end to it.This is how I have deal with the problem.
  1. I grab her front legs and take them out from under her and put her on her side in two quick moves. This really surprises her.
  2. I place my hand and forearm across her side (face, neck, and above the front leg).
  3. I say “no” in a stern and commanding voice.
  4. I pin her there until she stops struggling and trying to get up. When she relaxes, I keep her there for a few seconds.
  5. I take the treat away from her, letting her see me to let her that it is now mine since she is acting inappropriately
When she growled at my kids, I did the same, but I had my kids put their hands and forearms on her as well letting her know they are superior to her.
Some people may say this is mean, but it doesn’t hurt the dog. Also, the mother does the same with her paw and leg when a puppy does something inappropriately. She, of course, uses a growl instead of “no,” but the idea is the same.
Keep in mind that she is a puppy and still needs to learn boundaries like any other dog. With some time and diligence, she will make a good pet for you and your son. It sounds as if she has already bonded with your son. Hope this helps.
Chris Chuck
(owner of a black lab/pit mix)