I've been giving my two a little over 1/4 c. a day and they are doing well with it. Adie leaves some most of the time and Skeeter has even been leaving his occasionally so I KNOW they are getting enough. They both look at me when I put their bowls down as if to say "is that it?"
When I walk away the sniff each other's bowls then go back to their own and start eating. (Who says dogs don't have sense of fair play!) LOL