You can purchase these anti bird spikes from home depot.
Put them in the rock bed, when they land on them after jumping the fence they will get quite the surprise.
Or, go to the dollar store, buy a pump action toy shotgun and one night stay up late. When you see them jumping run towards them with your toy gun shouting slurs and cuss words and see if they shat their pants.
In other words, its time to beef up the ole home security.
Also, if they get injured its their own damn fault. Adolescent brats like that should have been spanked as a child, they were never properly discilplined and as such act like complete kanye's (jacka$$es)