Hi, I'm new to this forum but it seems like a very helpful group. We have a 3 week old gosling who has become weak overnight and can't stand and isn't eating very much. Generally he eats Dumor chick/gosling starter and fresh grass everyday. I read that it may be a vitamin deficiency, and that brewer's yeast could help. How much should I add to the food and/or water? Any other suggestions?