Hi all...new to this forum because I'm having problems (bet that's not new, lol). I have four dogs...two labs from the same breeder, a Parson Russell terrier and a lab/husky mix. Elvis, the lab/husky is the oldest at 11, then Ripley, lab at 8 yrs, Piper, the terrier is 7yrs and Davey, the other lab is almost 2. All these dogs we've had as puppies, none are new. But our youngest, Davey, has over the last several months developed fairly severe guarding behavior. It started with food, mostly...but has progressed to territory (our family room in the evening). She's gotten into fights with Piper and Elvis where we were afraid there might be injuries. Feeding time is stressful to the point we have to separate Davey from the other dogs. In the evening she randomly is growling at the other dogs as they hang around with us. Everyone is on edge...sometimes the other dogs go out their dog door to the outside...then she won't let them back in. We are at a loss as to what to do next. Have ordered the book "Fight" by Jean Donaldson as suggested. Any other ideas?