You know what's easier than raising your fence? Take a pair of scissors to one wing per chuck. They can't fly over a 4 ft fence with a clipped wing. 90% of the time, it works every time.
We did once, and I think it mostly worked. 1 chicken was still able to escape... so like 90% stayed in..
I am not a huge fan of the tall fence now that it's been a day. So I think I will have to cut it shorter and make the kids clip wings again. That will also help keep this chickens off the hot tub, sxs, ac unit, trailers, other fences, etc..