In 1989 I caught one the exact same way. It was also really young. I kept it in a cage for a couple days, feeding it raw meat, and then started taking it outside, with no tether. The third time outside it flew off. I guess that's when it was ready to go. It never occurred to me that something might have been wrong... I just assumed it was really young and wasn't quite strong enough to fly, yet. And I didn't want the dogs to get it.

You did a good thing.