I don’t know how old they are, that might have a bearing, but it sounds like a normal molt to me, though it’s a bit late. Still, I have a couple in the middle of a heavy molt right now. The days getting shorter is what triggers the molt, not the temperature. We’ve just passed the Winter Solstice so the days are gradually getting longer but mine have already started the molt. It sounds like yours have too.
Each chicken is an individual and does things like molt on their own schedule, within some bounds. Since you only have three, averages don’t mean a lot. You just don’t have enough for averages to balance out. So while yours may be late, that’s not unusual in so small a flock to have some late.
I would not be over-concerned about them getting cold later. Naked Necked (Turken) chickens have totally bare necks. They also have about half as many feathers as most other breeds, yet Turkens are known as a good cold weather breed. They can handle cold better than we often give them credit for.
