this is before I read this thread this was a long time ago maybe 15 years ago
Not saying this happens only to chihuahuas and beagle a raw diet is always a good diet unless your animal has a sensitive stomach and cant handle it. I have had many chihuahua and beagle on raw diet. (cooked)
It is possible for some small breeds ( and maybe even big breeds i think it really depends on the animal) can't handle a raw food diet. I know from first hand experience that my tea cup wired hair chihuahua and a beagle mix acted so sick and would whine and curl in a ball. it gave them stomach pain. It was a long time ago so not sure I think she may have had diarrhea. I went to vet for both times when my dogs got sick and vet says it cause they have sensitive stomachs nothing to bad they weren't dehydrated just change diet.
So I switched to Evo I got 2 different flavor of Evo and mixed them together. chihuahua got over her tummy pains and had normal stool again. Also tried it with Blue buffalo for the beagle and still use it today for my cats and my dogs its great.
Not saying you have to buy the brands i mentioned just that my wolf/dog and my short hair chihuahua plus cats loves both brands.
Also all the brands and categorize are put up great this is a very good and well put together thread.