I mixed things up a bit with one plot this year and planted just Purple Top Turnips in it. The deer hit it pretty good, but seems these guys have enjoyed it the most. There is some volunteer clover in the patch as well, from some previous plantings.
It must be the clover in there that they're eating, or maybe some sort of bug. Turnips don't offer much of anything for turkeys. But it's clear they're sure enjoying something in there!