Jettsmeow,first of all Welcome to the Forum,secondly,thank's for taking in stray kittys!
Cat Chows is junkfood,as is IAms and really anything you buy in the grocery-store,I am sorry to say!It's not only ash you don't want,but also corn and cornmeal,which is just empty fillers.
Try to find a store like Pet Smart or any Pet Food supplier,the food will be more expensive,but in the long run,you save by having healthier cats.
Of course,it goes without saying,we like to see some pics of our new kitty-members