OK, I looked this up on the forum before posting, so I know about the drawbacks that people have listed and I've tried to plan for these, so here's an idea that I had...around here people are often posting free sliders on craiglist, so I got to thinking...how about making a coop almost entirely out of sliding glass doors? using six or eight sliders plus framing - for an 8x12 or 12x12 coop. One small wall portion on one or both ends, to install a chicken door. Both sides if using 2 5-6' sliders, or one end if one is an oversize 7-8 ft. door. 1) Double-paned for insulation would be better but not mandatory because of where I live. Aluminum (vs wood) would be fine or even preferable for this type of use. 2) The structure's framing would have to be strong enough to support a roof with fewer support points - corners and in between the sliders on two or four sides. If this is an issue, do a shed-style roof with corrugated roofing. 3) The majority of them would remain closed in the winter, which minimizes the track mess problem (not using it, not a problem!). 4) They could be opened in warm weather for cross-ventilation. 5) There would still be an automatic chicken door - the chickens would not be using the sliding door, hence they are not open unless for ventilation. 6) Sliding screen material could be replaced or covered with hardware cloth for when doors are open. The cloth could even be screwed into the aluminum screen frame. 7) I would screw 1X6's against the inside tracks to keep out a good amount of the debris. 8) Built on a concrete foundation with a step up - less chance of outside debris getting in the slider. 9) Roof overhang, awnings and/or shades/shade cloth used on the south and west facing sides in the summer. I already have a bunch of 70% cloth. Better yet, find some with the shades inside the windows... 10) Vents at both ends under the peak of the roof for winter ventilation. 11) I could put stickers on the windows to discourage birds from flying into them...personally, I think the chickens are smarter than that and will figure out pretty quickly what their walls are....the bottom parts of the windows won't stay clean for long. Here are the pluses I see for this type of design: Greenhouse effect warms in the winter Open air ventilation cools in the summer (especially with use of shading) Cheaper construction costs (I think/hope, pls see below) Reusing salvaged materials Glass is easier to clean/disinfect than wood No need for separate people door or windows Less painting maintenance I live in the Pacific Northwest so we don't get super hot or super cold here for long periods of time. And it usually cools down at night when it's warm. My current coop is chain link dog kenneling with tarps on three sides for the winter, completely open air in the summer, and a dog kennel vinyl roof. My chickens have lived through the winter with protection from only the rain and wind, not the temps. The summer was not a problem for them, either, although again, the coop was completely open air. A question I have for builders, would using free or very cheap sliders cut down much on construction costs?..there wouldn't be much sheathing or siding materials/work and less painting...not sure how much time it would take to frame in the sliders vs. doing regular framing with a man door and at least one window. OK, shoot me down if you must...it will help me refine my plan or eventually discard it. Thanks!