I would protect them just in case. If they really want it, they'll be able to jump over it. Build a cage out of chicken wire to cover the lettuce and you'll be fine.

I suppose that it depends on the bunnies in your area but the ones here can definitely reach. The real question would be how devastated would you be if they ate your lettuce.

My beds are about 15" but because of the slight slope, one side may be more like 12". Last year they didn't seem to bother anything. I'm not convinced they won't, they just haven't. I meant to put up fencing last year, but didn't get to it. Once the plants were past seedling stage, I wasn't so worried that they'd wipe out the garden.

They'll be up on that. Bunny fence is needed.

Dan