One time we were looking to round up the chickens, and one was missing. We found it- on the neighbors roof. It was funny, but it reminds you they can fly for a short distance.
And we had a little bantam rooster that managed to fly up to the top of the run before we got it covered- and thats 5 feet high ( but for a banty, thats like.. 50 feet
)
I've really never had chickens in a fenced yard- those that had runs , the run was covered even on top. So I don't know if they would be determined enough to go check out and see if the grass is greener on the other side....
And we had a little bantam rooster that managed to fly up to the top of the run before we got it covered- and thats 5 feet high ( but for a banty, thats like.. 50 feet

I've really never had chickens in a fenced yard- those that had runs , the run was covered even on top. So I don't know if they would be determined enough to go check out and see if the grass is greener on the other side....