When Katie came to live with me Cal was just over 18 months and had been an only dog up until then. He was quite seriously possessive over food.
The first time I fed Katie, I gave Cal his food - raw mince and veggies. I took Katie's food - eukanuba from her breeder - to the other end of the enormous living room in the house we had then and put it in her cage. As soon as she started eating Cal left his bowl, charged the length of the room, roaring and ran into Katie's cage. My ex fed them once not long after that and didn't put Katie in her cage or put a lead on Cal. That time, Cal grabbed her by the face and threw her away from her bowl (my ex thought I'd been exagerating about Cal's reaction to Katie eating). Our living room was 25 feet long so it was a fair distance.
I worked on teaching Cal that Katie eating wasn't a big deal. I just kept putting food into his bowl while she ate. And at first, I kept him on a lead so that he couldn't charge her.
It didn't take him long to realise that Katie wasn't actually taking the food out of his mouth. I also made sure that I always rewarded any time Cal or Katie would tolerate eating next to each other when being given treats. And especially rewarded all times that they didn't snatch from each other. And I taught both of them a decent recall.
Today Cal's tolerance for dogs around food was really tested.
Today I was walking Cal and Cuillin off lead in the woods and Cuillin found a dead rabbit. He was merrily alternating between chewing on it and carrying it around so he didn't fall too far behind. Cal was very obviously interested in Cuillin's rabbit but would come when I called him, stay with me (even when Cuillin ran right past him with the rabbit in his mouth) and stay still while I worked on calling Cuillin away from the rabbit a few times. I only had banana and nut flapjacks to reward Cal with but he still stayed with me. :loveshower:
Eventually, I put Cal in a down stay, went over to Cuillin and called him to me. I had Cuillin stay with me then and let Cal go off and have a chew on the dead rabbit. Cuillin also was very good - he would play with me and chase bits of flapjack. He once went over to Cal and tried to chew the rabbit. Cal did nothing horrible to him - just gave him a bit of a stare - and Cuillin decided he'd rather be with me.
Not bad for Cal considering just how possessive he was over food. And considering that dead things found in the woods are his absolute favourite thing in the world - nothing I could ever give him could compare to a dead thing found on a walk.
And Cuillin was such a star too! He's only 8 months and he came away from a dead rabbit when called.