I feed in the evening also. If im going hunting that evening i do not feed. If i'm going even the next morning i don't feed the night before, when we get back they get fed if we caught hogs!
Ive done it the same way for 15years. I like them to be clean before a hunt. They get use to putting bacon on the end so when we get back i actually feel there bowls before i unload them, so they know thats like there treat! Works for me. I found out on a hunt a year ago in the middle of a 5 day hunt my old dog Superman loves him some peanut butter crackers, and he showed us he loved them after cold tracking a hog at noon a little over 5oo yards and bayed solid! (i didn't give him the crackers)