@Papa John59 Well I didn't really train them as such, but my entire property is fenced in. We did that when we moved here for the dog and the toddlers at that time. My chickens did manage to find some holes though, because I think they thought the 1200m2 was boring after a while, and it did bother one neighbour of mine. They were jumping a lower barrier I had, to access his property to cut my hedges. So he raised that and all is good now.
Sussex are heavy birds, they can fly, but not so high, about a half meter off the ground or so, that I have observed.
Those buckeyes are really cool, I see why you would want them, made in your home state and endangered. A real soul project! If only we had a star trek beam, to beam birds and hatching eggs to us, eh?
Have a great Sunday! and good luck contacting the poultry club.