Tilling does have it's place, like when have to create a fresh growing bed ASAP, or have a lot of soil amendments to incorporate, and I'll admit that I have a beautiful troybilt sitting in my garage that may get used every 3 years or so to make a new bed. IMO, routine tilling does not improve the texture or make up of your soil, instead, it disrupts it. By creating that nice fluffy bed of soil, you're breaking up the worm habitat, their tunnels which channel water, and creating hard pan under the depth of tilling from the constant and repetitive slapping of the tines. Try an experiment, buy a bale of mulch hay, and spread it over a small section of your garden to the depth of 6". Do it as soon as possible. Let it set for the winter. Do what ever else you do in the rest of the garden. Most folks let it set with bare soil exposed. If you sow a green manure, so much the better. In the spring, check both areas, compare the date of frost out, how dry the soil is, how soon you would be able to actually plant something. If you really want to give the area a head start, stick some pieces or re-bar or other dark colored metal posts in the ground throughout the area. The metal collects sun energy, heats up, thaws the snow around the base of the metal, when the sun hits the bare or (mulched ground) the snow melts even faster.
I don't believe you're wasting time insulating the metal part of your roof. One of the books I'm reading now, recommends that the north wall of a green house be both insulated, and contain a heat sink. I'm guessing that your coop is oriented with the metal to the north, so it makes sense to insulate it, especially where it's metal which would wick heat away from the birds. If you could get some cinder blocks and paint them black, or provide any other thermal mass to store heat, you'd be golden. Perhaps I'll try a few black cinder blocks in my garden!
