We picked up 3/8x24 inch pine boards a few inches tall, tall enough to keep them in. Purchases at Lowe's for about $1.79 each, cheap insurance. And I actually found some boards that had a damaged corner or chipped edge. Those I pointed out to a Lowe's clerk who promptly gave me a deal of 50% off.
Gary cut a bottom corner on each end so that it would fit snug up against the urine guards that have a corresponding bend on the bottom. They fit pretty snug and are further held in place with a couple of bolts with wing nuts for easy removal when not needed.
We don't fool ourselves into thinking the does won't chew on them but at least they'll only chew from the top. No different than the ones who chew on the nest boxes. Fiber food?
Pictured is the older brood doe, "Saynora's Hope", love her perfect crown and short well shaped head hugger ears.