I read this book to my kids for bedtime last spring, and I read Farely Mowat's classic when I was young myself. We used to have Great Horned Owls hanging out in a tree next to our house at sunset and we'd call back and forth.
If an owl is raised by a rescue group with puppets, it won't become imprinted on humans and if it recovers full wing function, it can be released back into the wild.
I'm assuming since you've had it for a while that the injuries were too much to recover from? You may have that pet for a long while.
Did you ever read Owls in the Family? That was a wonderful book.