RE: Pet food quantity - large package or small package?
I think it is important to buy the right sized bags of food for the size and amount of pets that you have.
When I used to have two Great Danes, I not only bought the largest bag of dog food that I could find at the feed store, I also went to the butcher shop, and asked them for any large bones from the beef they were cutting up. They would usually send me home with a huge garbage can of meat bones and fat scraps, which I dumped out under the trees for the dogs to chew on as they pleased.
Now, I only have these tiny little dogs, and except for Tootsie, they are older dogs, as well. So I just get the small bags of dog food, and make sure that it is the smallest size of kibble that I can find.
Around the size of a pea is about right for my little dogs. I also get them the little packages of moist dog food, and share that between them every day or so, so they are not lacking in food to eat.