Have you considered the reason they may have been sitting like that?
Also, you do know they need a big yard, like half an acre for the two you have and acres to have six.
They don't take all that many years to grow big.
Maybe @ben awes can fill you in on years and size. He has a few he is raising. I don't think any of his is 10 yet and and they have some good size.
Would be nice if you could put them on some grass and weeds to graze on.