Trying to pinpoint source of aggression
I will try to keep this as short as possible...
Have had Madison (7 y/o female) since she was 2 months old. She has always been mostly submissive with me. She is always stubborn with nail trimming and baths, but always gives up after a few minutes. The only issue she has is children. I am not really sure why, but she is not a fan of children. Never had any kind of incident, and I always keep a close eye on her while out in the yard (lots of kids in the neighborhood) to prevent any incidents. Never any food aggression, and has never had any major issues with other dogs.
Sheldon (1 y/o male) has just turned 1 this month. December will be a year since I've had him. He is full of energy, and has a bit of a dominant attitude. He has gotten along with all dogs he has come across, and has even had a couple trips to the dog park with no issues. I have been having some aggression issues with him...
At first it was mostly around food. When preparing their food, he would get overly anxious, and would go after Madison if she tried to get close to the food. That was mostly solved once I got them in a routine. I now make them 'go sit down' and wait, which they both do nicely. Once the food is ready, i carry the bowls outside and they follow. Once they sit, they get their bowl. They have kind of created their own part of the routine where, when finished, they switch to check out each others bowls.
Now, It has happened a few times if Madison gets too close to something that he thinks is 'his' (antlers, people, toys, etc.) And, the other night I had a friend from work over... and Sheldon went after Madison twice. First was kind of randomly while my friend was playing with the two of them on the floor. Sheldon got about 8 minutes in his crate to calm down, then I took them both outside where they always play without any issues. The second was (what appeared to be) because Sheldon thought Madison was going to take an antler that he apparently 'owns'.
They play pretty well outside, and getting better inside. It took Madison a few months to warm up to him, but she even chases him now, and shows excitement while playing. I even catch them laying together on occasion. I swear she tries to pretend she doesn't like him... until she thinks I'm not watching.
They ALWAYS start with Sheldon approaching Madison and getting his head side by side with hers, then it's triggered and they erupt. In every instance Madison basically gives up and just falls onto her side. Sheldon always ends up on top, and sort of goes for her scruff. It seems to be more snarling.. mouths open... teeth showing... than anything. Never had a significant bite during an incident.
After pinpointing the food issue we were problem free for a month or so, until the other night when my friend from work was over. The only other time Sheldon showed signs of an 'outburst' was during a recent thunderstorm. Madison gets very nervous during storms... shaking, panting, hiding in corners, etc. He started following her around and acting overly anxious, but I was right on top of him and stopped it before it escalated.
Lastly... my girlfriend claims that it ONLY happens when I am home. I don't get nervous or anything so I'm not sure if it's actually because of me. I do watch him closely, especially when I notice him showing the usual signs, but I don't lose my cool.. so I'm not sure if I am actually a reason why it happens.
Sorry this is so long... wanted to include all of the details.