First thing I do is flip it over and read the ingredients, most of the time whatever it consist of most is the first then so on, not always the case, I try to avoid anything if the first ingredients are corn or wheat, second thing I look for is the fiber content, low fiber means less grain and more meat based kibble, not saying my way is right or the only way but it's just a personal preference...
Depends on time of year it is as to what feed I'm feeding, a lot of your cheaper feeds will show a high protein but it may not be a source of protein a dog can digest (absorbed by body) some feed manufacturers add hair to the formula to increase the protein content on paper but in the end result your dogs can't use it....
Thats good info i never new that. So what kind of food do u use?