Rabbit's Nest

We have a little rabbit's nest in the backyard (but unfortunately on Trudy's side of the fence).
I've put a little table over top of it to keep Trudy away, but I'm not sure if that will continue to work once the babies are big enough to get out of the hole. 
This morning when I let Trudy out, I saw the mother run away.
Might need to put in another sub-fence...