Weasels do come out during day-time hours, but I think they are more active at night. I can't recall an instance of anyone reporting a daylight loss to a weasel.

They can get through a hole not much bigger than a quarter. They don't gnaw like a rat, however, so any tight wood chickenhouse should keep them out at night, providing that you use hardware cloth over the windows and latch the pop-hole.

Mink are fairly easy to trap using a live trap baited with a sardine. The smell of the bait attracts them from some distance away. I'd try the same for a weasel, but if it doesn't work, then check out other types of bait.

I rather doubt you will have losses during the day if the birds can free range. Weasels are the biggest problem when they find themselves inside an enclosure with many chickens. This situation would not arise in nature and they seem to have no "off" switch to limit their killing.

Weasels are not strong animals - they are SKINNY animals. And they don't climb well, although they can scramble. 1/2 or 3/8 inch hardware cloth all around is enough to keep them out.

The skunks are a different problem - bigger and stronger. Make sure the hardware cloth is well-fastened, and check it regularly.

Coyotes will snatch free-range chickens.