What to do since my baby fawns won't eat?

my family and i bought two baby fawns two days ago, at 7 days old. so today they're nine days old. they're both girls and one is bigger than the other. they were both fine the day they got here and were settling to the new environment but yesterday morning the larger fawn didn't want to eat for her first feeding, second, third or fourth. the other just gobbles it all down in a minute. today their feeding is supposed to go up another half oz but the larger one still won't eat. her digestive system seems to be working regularly so I don't know what the case is... help?