Actually, that's not the best idea. Even though the avics are arboreal, the crix can easily be a disturbance. Especially if there's cork bark or other means by which the crix can climb. Also that fact that the crix deposit waste, and lay eggs as well. It's not a good idea at all to just let crix inhabit the same enclosure as your T. Also, if the T is approaching a molt (which is the most common reason for uneaten prey) you definitely don't want any crix loose in there. They can cause serious stress to a T during the molting process.
T.L., here's what ya do. When feeding, put the # of crix that your T will usually eat. 2, 3 at the most at a time. You can usually give the T overnight to eat them but any that remain should be removed. If your T isn't taking the crix, try again in a couple of days. As long as the T looks nice and healthy there's not much to worry about if it goes a little while without food. (Make sure that fresh water is always available though.)
If your Avic doesn't eat after a couple tries, it may be approaching a molt. Keep an eye on it and try not to disturb it. You may even wait as much as a week before trying another feeding. This won't harm the T at all.
Oh, and like Wade said, the "fanging" the legs does sound like grooming behavior. Perfectly normal.