One of the challenges I'm having designing my coop/run is that I'm planning to move slowly and keep a fairly small flock. My city only allows six hens at a time, and I'd like to ensure I have the space for younger birds periodically, so I'd only be starting with 2-3 this coming year, then add another 1-2 after a year or two, etc. (Note: I'm being an optimist and assuming about an 8 year lifespan on my hens; random death/loss will be factored in as needed once the theoretical chickens start being actual chickens.) While it seems like chickens don't object to more room than is necessary -- I'm really hoping to stay close to that 4' sq coop/10' sq run ideal if I can! -- I worry about a duo or trio being able to keep their coop warm enough in a coop made for six during a Missouri winter. I don't want my future hens to be chickensicles! On the other hand, building a coop cozy enough for two or three now will mean a rebuild or renovation further on down the line. Anybody have experience or advice with how to manage this kind of thing? My inclination is to build a smaller coop -- 3'x4' with either a 4'x6' or 4'x8' run -- for the initial 2-3 and then expand it in 2-4 years when I get closer to the 6 chicken mark, but there's definitely a part of me that grits its teeth at what feels uncomfortably like planned obsolescence. Thoughts? Experiences? Good ideas?