Do you have any pictures of your set up?They may well change their minds when the weather changes. On the other hand, my runner ducks don't seem to mind cold, snow and/or wintry wind at all. With the option of staying in their shelter, they often just hang out in the snow.
Now, the chickens are a whole other story -- some of them seem to think snow is lethal!
My ducks' "coop" is a converted chicken tractor with a partially covered roof, and I temporarily attach side "walls" of plywood to block winter wind on the north and west sides. Otherwise, it's a big hardware-cloth-wrapped structure where they can take shelter when they feel the need. Of course, they are locked in every night to keep predators away.
It quite simple and in located in ct so we have some.negative degree nights and very cold daysKnowing what your run set up is like would help with suggestions.
Can you give us more info?
Where in the world are you located?
Can you post a few pics of the set up?
Thank you. Do you have pictures of your coop by anychance?I think I see one of your issues. Ducks and ramps (especially ones with no cleats and that are narrow) are difficult at best and can be impossible for them to navigate. Narrow and they fall off the sides and no cleats there is nothing preventing a slide.
I found mine were willing and able to hop onto a 1 foot tall platform that had TONS of landing space but a ramp to that same platform was more challenging even though it was 18" wide and had gripper tape. That ramp was their access to the pool.....somewhere I hey WANTED to go.
To get into the duck house was just 5" up and had a long 18" wide ramp. They went in on their own every night.
Yours will need protection from the weather. Especially the heavy overnight snows.
I would start working on stairs for them if you cannot get the coop to ground (or near ground) level. A way to cover the run that won't cave in under snow load would certainly help too.
Edited.....There are cleats after all. I was looking at the baby pic not the one where they are feathered out.