Aggressive Tired Puppy
I have two sibling puppies that are about 14 weeks old. At around 11 weeks, one of the puppies started getting very aggressive when it was tired, at around 7 PM. Once it is tired and lays down, it does not want to move. If you try to pick it up, put a leash on it, pet it on its back or hind quarters, it will bite hard enough to draw blood (significant blood drawn about 5 times). You can pet its head.
Both puppies are boys (for now) and are scheduled to be fixed in a few weeks. also, fyi, they are golden retrievers.
Any thoughts as to what to do when a puppy gets nasty like this?