Put up a fence! If the chickens feel they have enough room to roam they won't bother to jump over it even though they can. I had to do that because of coyotes and dogs trying to get my chickens during the day while they free range. They have a 4 foot fenced in area about 50' x 50'. They have never bothered (so far!) to jump over or fly over the fence. They are content in this area, you may want to try it. Use t-posts and goat fencing, you can always take it down and take it with you when/if you move! Good luck.
View attachment 1426207