I know what you mean. And at 3 weeks they are about to really start to shoot up. I have a major hawk concern as well, but at 5 weeks both my Kahkis and Muscovies seemed to be fed up with the tight quarters in the house and short outings. I have way too much going on to supervise constantly for extended periods of time. So, at five weeks I let them loose in their large fenced area, and pray. We live on the edge of a huge section of BLM that boarders NF, so predators are everywhere. My first Kahkis have reached adult size, regaurdless of the constant flow of Hawks and Eagles through out our little valley, and I worry a bit less. So, I don't have a good answer. I would, like you said, wait at least a couple of weeks more.