If my dad was still alive I would ask him but here goes. We have chickens - layers. Because it is so

[procon]

3. Contact your local extension service

They have expert info that pertains to your regional issue.

In general practice, dirty birds make for dirty eggs, so look to your coup housekeeping, so here's a few tips that I use that may give you some other ideas.

Deep bedding with daily scratch feed will help keep the floor cleaner. Provide a clean sand box for the birds to "bathe" in and that will encourage them to preen and keep their feathers clean.

If your coop has electricity, keep the lights on for at least 12 hours a day during the winter months to encourage to birds to be active. Also use a warm water dispenser to keep them drinking.

Locate your roost and the feeding area away from the egg boxes. Use a different filler in the laying boxes than what you use for bedding, and use boxes that are covered to keep the birds from loitering on them and fouling the eggs.

Don't over-crowd the birds if they a confined, even in cold weather they can still go out if you provide them with a ground cover like straw so they don't have to stand on the snow. To protect them from the elements, you can make an enclosed lean-to shelter from plastic sheeting attached to the sunny side (usually a southern exposure) of the coop. This is a quick and easy way to get them out and actively scratching and preening, and the sun will warm it like a greenhouse.