The rabbits ate mine the last couple of summers. First they chop off the flower heads and then begin eating the rest of the plant. I ended up with stubby plant stalks. You can built a little wire cage around a plant or group or plants to see if that stops the damage. Just buy some wire mesh from the hardware store. I think it's something like $10 a roll and easy to cut with snips.
Fairy tales do not tell children the dragons exist. Children already know that dragons exist. Fairy tales tell children the dragons can be killed. - G. K. Chesterton