My Russian tort does the same thing! She will have the entire backyard, but she makes a beeline for the fence. Walking back and forth along it trying to squeeze under it. If she would just turn around she could roam the whole yard almost!
My Russians do the same thing. I realize in nature they may have a territory of some 100 acres, but you'd think that if they have food and water provided, they might downgrade their ranging requirements a bit. Nope.
Don't let her bang into that chain link fence too much. My guys did it so much that they scratched their first vertebral scute in almost the same spot.
That one blade of grass on tue other side...lol...so a few times a week I will take some of the CDTs for a walk around the property here....so funny, Ghamara was doing this thing he does at the fence that let's me know his spot in rotation for the walk is next...it is a little dance thing he does at high speed...so I go over and unlock his gate..throw open the gate ....he stomps on over and walks out....well instead of his normal path out of the gate he banks a hard right which brings him directly on the outside of his yard fence to the exact spot he was doing his dance...he immediately went to the apricot mallow bush that has sprouted up and had a big ole leaf on it...he chomped that leaf in one swoop...then kicked out his feet and laid there for a few minutes very proud of himself that he got that leaf I bet he had been watching grow to exact perfection....lol....
they dont understand invisible barriers, they will do the same thing if put in a glass aquarium. you could try to buy those green/brown plastic slats and cut them down to like 6-8" and do the perimeter. you can kinda see through them though if you walk by them be at a certain angle but that may not be such a big deal. on my tort table i have some plexi-glass windows but they are 3-4" above the substrate and my Russians will stretch their neck out and try to climb on each other just to see out. they notice my dogs that walk by, and i think they "know" there is something else out there.