My understanding is that you don't want the gear to freeze in the gear
well, so you leave it down after takeoff to ensure that anything that's
going to freeze will, and then if the gear is going to get stuck it's
stuck down, not up.

--
Ben Jackson

http://www.ben.com/

That's called fixed gear, down and welded.

I spent lots of hours in a Mooney in the northeast, winter and night, never
took special precautions with the gear when on an inch of snow or slush. I
don't remember a runway being sluch covered, but taxiways had been, and I'm
guessing the takeoff run was enough to remove whatever slush might have
accumulated. It may also be people who live in colder areas than Massachusetts
have to do things differently. There's nothing in the approved manual that
says anything about special care (that I remember, at least)