Hi all!  Rowdy is a very friendly boy, loves other dogs and animals, loves going to the dog parks and playing with others, he's not aggressive with toys at all.  He eats really fast normally, so I bought him a special bowl with the bumps in it to make him eat slower.  He has never shown any food aggression with people, I am sure to check him regularly, for example putting my hand on or near his bowl while he's eating... no reaction, he just eats and carries on. 

Tonight, we've just discovered he is extremely food aggressive with other dogs. My parent's mini-doxie, Penny, has been semi-aggressive with him this week while we are visiting, but food was never in the picture. My parent's have 3 dogs, who all eat in the kitchen, and Rowdy eats outside on his own. My dad was in the kitchen with the dogs making something to eat, and while the pantry door was open, Rowdy was investigating the dog food bag. Penny walked up to him while he was at it and they started to go at it pretty bad. Then it would up with my dad, brother and me pulling them off each other. I've never seen this side to Rowdy.

I can understand that he isn't used to being around dog food with other dogs, but this is a HUGE no-no.  Any tips will be greatly appreciated on how I can correct this behavior. The problem is, we don't have any other animals at home so it's never really a worry at home. Is it strange that he is not toy-aggressive and overly friendly/playful with other animals, but has a serious food issue?

Please help! And please keep in mind, I am on a super limited budget and cannot afford any personal training for him. (as much as I would love to do it)

Thanks!!!