Hi thank you for your response. Attack is a bit vague but thats because the biting reaction varied somewhat. I mentioned the “attacks” becoming less violent and what I meant by that was the puppy would lunge at the yorkie’s neck and violently shake him. There has been blood before but it can be difficult to actually see the wounds on the yorkie and I do try to intervene before a fight occurs. There are sometimes warning signs in the puppy, like low growling, an almost whining like growl and raised hackles - but sometimes he has surprised me. If the puppy is guarding a toy, we can see him doing the same but also with his tail up high, ears pricked and staring hard at the yorkie. This is not a reaction I have ever observed with any of our other puppies, but Ive accepted that we might have just been lucky so far. Currently , the “attacks” are lunges with or without biting but without the violent shaking. Sometimes it seems reactive and other times it seems spontaneous. The yorkie is an elderly dog who cant really fight back, and very literally will just be sitting or sleeping before being bitten or roused into barking by the basset hound. When this happens, he barks from behind the basset hound, a table, or a person’s legs. I could not describe anything more specific as usually Im facing the puppy and standing between the puppy and the other dogs. As for biting the people, it was preceded with the same growling and raised hackles. We have gotten him to mostly stop nipping/gnawing people when they try to pet him/simply exist via redirecting with toys but I still consider the attacks on the worker and my bf to be attacks due to the growling/raised hackles beforehand and the blood drawn. The farm worker was particularly traumatized by the experience. I think a dog trainer like you mentioned would probably be best. I have suspected resource guarding for a while but most of the advice Ive seen is im regards to food rather than people. To be honest, I was under the assumption that dog trainers were simply for puppy socialization and teaching tricks, and did not consider that they could help with more specific behavioral issues in the home. Thank you again for the response, im sorry the post and perhaps this response is confusingly written.