ok, I am about to have three sets of chicks. I have 21 chicks that are 10 weeks old, 9 chicks and 5 ducks that are 2 weeks old, and in a couple of weeks I will have about 30 new chicks. So far I have kept them seperate because the older ones might pick on the little guys. So, my question is...how long do I have to wait until I put them all together. The two week olds seem too tiny to defend themselves.