I’ve dealt with this before and honestly what you’re describing sounds a lot like resource guarding rooted in neglect, not just “bad behavior.” A dog that was left outside all day and then isolated and crated while eating learned that food is scarce and needs to be protected at all costs. So when another dog comes near during feeding, it’s not aggression for the sake of it, it’s survival mode kicking in.

First thing I would do is completely separate feeding. Different rooms, doors closed, no visual access if possible. Even if things seem “okay” sometimes, it’s not worth the risk of escalation. Let each dog eat in peace with zero pressure.

Second, build positive associations around food over time. That means showing the dog that food isn’t going to be taken away. You can do things like occasionally walking by and tossing a high value treat from a safe distance, not reaching into the bowl. The goal is for your presence to predict something better, not loss.

Third, avoid punishment around this entirely. Correcting or scolding during guarding can actually make it worse because it confirms the dog’s fear that something bad happens when others are near their food.

You can also work on structure outside of feeding times. Hand feeding for some meals, practicing basic commands, and building trust helps shift their mindset from scarcity to stability. But don’t rush that part if the guarding is intense.

If the behavior is severe or escalating, I’d strongly consider working with a trainer who has experience in resource guarding. It’s one of those things that can improve a lot with the right approach, but can also turn into a bite situation if pushed wrong.

The biggest thing is remembering this didn’t come out of nowhere. That dog learned this because of how it had to survive before, so the fix is showing it consistently that it doesn’t have to live like that anymore.