concerned about dog food

I adopted Pixie from a vet, and assumed (oh, bad, bad, thing to do) that the food the vet put her on was the best for her. After all, a vet is there to take care of our animals.
Well, 5 weeks into owning Pixie, I asked around about possibly controlling some of her anxiety through diet. That is when my eyes were opened to the horrifying world of pet food. The more I research, the more I'm disgusted. Soylent Green...
I have discovered that the leading brands, the brands I have come to trust over the years, put horrible stuff in pet food. Dogs can't digest corn, and many use corn as a main ingredient.
So, along with reading my kids food labels, I'm now reading dog food labels. But, it's coming more and more possible that I will cook for my dog. Except for a few supplements, everything dogs need, I serve my family. Normally, cooking for dogs is expensive - but Pixie is tiny. She finally hit the over 5# mark!
I'm still researching, and watching her.
This week, she is eating ground chuck. The little rascal actually pulls green beans out, but dogs don't really need veggies, and there are better ones for her. I add a little oatmeal to is, fish oil,and mix with a bit of her kibble, to convert her over. She hasn't liked chicken so far.
Since I can't repost the study info, I can tell these things.
Dog food should have specific meats as the first few ingredients - beef, chicken, pork. Not by products. Fats and meal should specify which fat and meal - not just animal fat. Check chemicals - some that have been banned from human food is in our dog food. These additives are known carcinogens and are not regulated by any animal agency.
All the information I've read is based on findings by the US gov and veterinary groups. BUT - I take studies with a grain of salt. You can find studies showing coffee is good and bad for you.
Pixie, will be enjoying healthier foods cooked by me, and I will supplement her with a natural dog food.