Erica's feedings vary kinda as well. How long has he been eating less for? Erica was steadily eating 4oz when given a bottle, but then started only eating around 3oz again. But sometimes she will eat 2 bottles (4oz each) within like 4-5 hours. I'm not sure why it varies so much. When I BF her, I'm not sure how much tho. As long as you are getting a good amount of wet diapers he should be fine.