Chckens are kinda like a group of young boys that mom let out for the day. They wonder and wonder and stay focused on the group unti they get a good distance from home and then wonder how they got there. If they are jumping the fence then unfortunately you are going to have to be the fence police and train them to stay within this boundry. It may take a few tries, but they will eventually get the idea. Chickens can be "redirected", the roos do it all the time to the hens. Watch them sometimes and learn. You do not have to let them out for the entire day. The do tend to go to roost a night, so a late afternoon outing would probably do them.