My leghorns have never tried to fly over my 6 foot fence. I feel lucky.My white leghorns & brown leghorns can clear 5ft w/o touching the top. They are flighty birds. They get clipped. The Easters can almost, but can't- but still try.
Rocks/javas/austra's/buffs/reds are too big of a bird.
My Dotte's are good flight birds.
I placed a hot wire/ground wire set up above my egg house run. It extends the fence up to about 5-1/2', but the leg horns think they are seagulls.. Pain in the butt they are. Thank God there are only 24 of them.