Just over a week ago two of my does each gave birth to twins. One set is doing great and they have a model mama. The second set seem to be struggling. Their mother isn't interested in nursing for more than a few seconds at a time and they are very thin compared to the other babies. I've been trying to bottle feed, but after 5 days they are still not accepting the bottle. I've tried a couple different nipples and different ways of holding them, covered their eyes and they still fight it. Any ideas what I'm doing wrong? I've bottle-fed goats before with no issue, but these guys are giving me a run for my money.