Ok. If that’s what Wikipedia says.
Badger(mäyrä), pine-marten(näätä) have full winter hide still in the end of legal hunting season to end of March. And raccoon dog(supikoira) start to lose their winter fur around mid-April.
Colder winters like ‘86-‘87 the furs on hare and foxes were thicker than on mild winters, say ‘99-‘00
But sure, let’s go with daylight. With that note, do the fur bearer breeders/fur farmers cover their production cages from light or not? (No, they’re not covered from natural light...)
* JP_Finn shrug shoulders