It's really great that you've cared enough to volunteer and taken the opportunities to learn some good things about animal care. I wish more people were as curious and caring and eager to learn as you.
You're on the right track with reading the ingredients, however, they only tell part of the story. Chicken may be the second - or even first - ingredient, but just because it's chicken doesn't mean it's something you want to feed your dog. That "chicken" is very likely to be feet, feathers, or any sort of scrap parts from highly processed sources that have been treated with lots and lots of chemicals and hormones. The same goes for beef, lamb, or any other meat (??) ingredient in most widely marketed commercial dog and cat foods. The stuff that gets fed to our pets by major manufacturers makes those skinny "red racer" hot dogs look like health food. My Dad was buying one of the better selling dry dog foods for my first German Shepherd, and he was eating it, lots of it, but he was losing weight and not looking or acting right. Our vet told us he was suffering from malnutrition. We changed to a good dog food, and he was back to his old energetic self. He lived to be over fifteen, and caught a starling that was stealing his food the day he died.
By the way, love your forum name, "Brattina!"