They know the game, and just hop to just the edge of the fence and wait for Abby, and as Abby runs towards them, make one hop through the fence and then just sit there and laugh at Abby who runs at about the speed of molasses (and if she gets close she just "points" so the bunnies are in no danger). It's even funnier when she tries to "sneak up on them" and they hop through the fence at the last minute.
"Hasta La Vista Baby!"
It's a game for all involved I think. It's gotten to the point that when I'm letting Abby out into the sunporch to start the rabbit hunt I'm humming the Mission Impossible Song but it's-
Bun, bun, bun bun, BUN BUN bun bun.