I have a couple of rouen ducks about 7 weeks old. I was putting a tablespoon of brewers yeast in each cup of chicken crumbles and they were eating quite a bit. I have now started using a brewers yeast with garlic in it and now they pretty much won't touch the food. They probably eat maybe 20% of the amount they did before the switch. I'm wondering if I should just buy some regular brewers yeast and go back to that or if they will start to eat more if they get hungry? Along those same lines,I'm wondering will they absolutely not eat and starve themselves to death? I have no experience with ducks or chickens only a mini pig, but I have been doing alot of reading since I bought these ducks. Thanks.