There is a fellow on Oklahoma Gardening Network on Facebook who seems to be an expert on palms. Are you a member? Someone here may know, I certainly don't.

Windmill palms need well-drained soil and their foliage can turn yellow if your soil is staying wetter than they like. This, in turn, can lead to root rot if the soil stays too wet for too long. That might be the issue you're seeing unless somehow all the winter rain has somehow missed your place, but it also might be the cold weather too. It could be a nutrient issue because nitrogen in the soil is not as readily available in cold weather, but I wouldn't feed it now with the cold weather and possible ice/snow or whatever in the forecast for next week. You don't want to feed it, push new growth, and then have the new growth freeze.