I have a 7 month old pitbull puppy. She was a rescue and our vet believes she was bred for fighting, so I've been very diligent with training and positive reinforcement. I haven't had any problems other than typical puppy stuff. She never had any problems with growling at anything/anybody for any reason. But I noticed that she started growling at my other dog when she was eating. Then she growled at me while eating when I tried to pet her. She just completed her first heat (which I thought was weird for a 7 month old puppy). Could that have caused this new aggression? How do I correct it?
Thank you for writing. Good for you for working so diligently with her, and using a positive reinforcement approach! Your young female going into heat at 7 months would be considered "normal" since some female dogs will have their first heat cycle as early as 6-9 months of age. Although some females will have conflict with other (especially intact/non-spayed) females during their heat cycles, I'm inclined to believe you may have a different problem going on, that has nothing much to do with your young female's heat cycle.
From what you've written, it sounds like there's tension brewing between the dogs during meal times. I also suspect that when she growled at you as you tried to pet her while she was eating, the pressure/tension from being fed near to your other dog may have been a contributing factor.
Since you don't mention actively having done conditioning exercises to teach her to feel happy when you're around her food bowl (including working up to touching her as she eats) I'm suspecting that needs some work on it's own. Teaching her to look forward to your being around her food bowl while she eats first (no touching!) and systematically working up to touching/petting while she eats when she's ready for that (see the links below for more) is the way to go, but you'll need to work the program with her behind closed doors - without your other dog anywhere around - as the additional pressure/tension from the presence of the other dog is likely impacting her behavior.
Read the following links for more tips and information:
Concerning behavior at food bowl while eating
Help for a Resource Guarding Puppy
Resource Guarding - What It Is, How to Prevent It
As for addressing the brewing resource guarding problem between your 2 dogs, the following links focus on problems between dogs who live together in the same household -- and the fact that resources (food, bones, toys, etc.) are the most common source of trouble. Better management to prevent tension from continuing, or escalating between your dogs is the most crucial first step.
Please note: While the specifics of the problem written about aren't exactly what you're experiencing, read the information thoroughly, you should find it helpful to your situation.
Dog Fights and Fear
See this article for more on resource guarding between dogs - it's the most common cause of dog/dog relationship problems! http://www.whole-dog-journal.com/issues/14_10/features/Resource-Guarding-Behavior-Modification_20368-1.html
Worried about how your older, adult dog and your new puppy are getting along? This article Is This Okay? Typical Interactions between Puppies and Adult Dogs provides great information that will teach you how to identify what's normal, and what may be cause for concern, as they learn to live together.
Feel free to visit our Training Tips & Behavior page, for more. You don't mention where you live, but if you live in our area, you may want to consider a private in-home consultation for more help. Let us know and we'll be happy to provide more details on that. If you do not live in our service area, Click here for our FAQ page, where you'll find help for locating a qualified positive reinforcement professional in your area.
I hope this helps, and thanks again for writing.
Lisa Patrona Dip. CBST, CPDT-KA, ACDBC