Agreed, my bantam mille fluer eats everything from about 12 inches from the ground up, if your plants are mature to survive that, have at it! I have some beautiful snap dragons that have totally bare stem until about 12 inches up!
Like others before me mentioned, great little tillers, just be careful though, worms are a gardeners good friend in the fall winter and early spring, your chickens will eat at least their body weight and about 3 times more of worms if they get a chance!
I am off this afternoon to buy some picket fence materials to make a run for them, i have fenced most of teh garden off but like the DW said why fence away the flowers if we cant sit and enjoy them. Plus this will prevent little piles of chicken manure just sitting there asking the resident beagle to roll in them, so picket fence that will me mobile and next year i will garden this years run!