I need everyone's input on what to do about dog food...mine didn't eat any of the can, well Max did in November the Nutro Max, but NOW my concern is the crap about dry....I have tried my best to feed them good stuff, but now I am afraid I am killing them

...I have Max (GSD) and the cats on Iams...I know not the best but Max will eat it(picky) and the cats I thought was better then Meow Mix, very picky eaters, the yorkies are on Royal Canin Yorkie, and I was going to switch Max after his was done with his big bag of Iams more than half full.....SO MY QUESTION is do I stop...and go to something else and what is safe to feed them...I can't cook all of them food, I know I should but I don't think I could keep up...so what do I do....