We don't have that problem but we do have coyotes that can jump the fence. We installed coyote rollers. They attach to the top of a fence and roll when the paws touch them. Even bigger birds can't sit in them. Tell your friend to google "coyote rollers". There is a video showing a dog trying to jump over and can't. These can be ordered and shipped. Luckily, the guy lives in my city and came over and installed them for me. He is a retired cop.
__________________  RIP my darling little Gina |