I've been giving my baby formula for the past couple of weeks, he takes a bottle fine the only problem is he dosent drink much. On the tub it tells me he needs around 7oz of milk but I can only get him to drink around 4-5 oz sometimes less every 2-3 hours. I try and encourage him to drink more and go longer between the feeds but I think it must be where he was used to breastfeeding/'snacking' more frequently. Any advice or is this normal?