cyber sibes- I am glad your dogs are doing well- however the fact is- only the "heart"/pulp of corn can be digested even finely ground still turns into a filler that is passed in the stool.
Rules with diets- if you see no side affects- probably not to switch. However- this is taking place.
If I knew if your dogs have allergies ( which I rather doubt considering what they are eating now.. ) I can post a few ideas.
There are countless threads on food on this site. So a search and you will get more information.