My twins were bad eaters when they were first born but then aftera while started finishing bottles in 25-30 minutes but for the last two weeks they take an hour and half the time don't finish. They fight most of it waving their tounges around or crying. They get half breast milk and half neosure preemie formula for my son and half enfacare preemie formula for my daughter (she threw up with neosure). He is on medela bottles and she uses avent but we tried different bottles, faster nipples and no change. They don't even do well after their 6 hour stretches at night and we just dropped one night bottle and they aren't making up the difference. They are 3 months. I am frustrated and don't know what to do.