have two precious baby muscovy ducklings that are 6-8 weeks old(not sure, but theyre pretty well feathered). i just got back from a four day trip, during which my sister took care of them, but when i got back they had no food or water and their cage was a bit nasty, so i fed and watered them. then i noticed that one had mucus dribbling from her beak and as i watched she threw up clear/white mucus, and the other is gagging just a little. i gave them a deeper water bowl and havent seen her do it since so maybe it was just all that water, but ive never had ducks before. is this normal? do i need to do something?