A Green Imported Cabbageworm and Cross-striped Cabbageworm is a common pest of cabbage family members and both VERY bad and damaging. They will do a number on broccoli, cauliflower, kale, kohlrabi, mustard, radish, turnip, etc.
Although, we've had oodles of Cabbage Moths this past Summer these pests didn't appear until the Fall. They've done a number on the radish greens and now doing the same to the Kale.
The good news is that the chickens love them, but there are just too many and too small to pick all.