A cold snap is coming for a few days it will be in the teens overnight and 30's in the day highs. The onsies the nakeds were in didn't have any or much wing coverage, so I went and got onsies w/ long sleeves and modified the sleeves to better fit the wings for wing sleeves and so they wouldn't be long enough to drag and get wet. Now they all have fresh new onsies w/ sleeves on under the wool sweaters. Rudy seems to mind the cold more then the others, he was the most chilled under his clothes. I had been cutting the sleeves off and making pants w/ the sleeves, but the wool sweaters seem to cover the outer thighs well enough to forgo the pants. We'll see how it goes.
Good luck. I've noticed a similar thing, a particular bird minding the cold more than the others.. and there's even one that acts like it isn't cold at all. There was frost on the ground this morning and several times last couple weeks.