The roof is done! After I did about 2/3rds of the shingling, Lemontree tried her hand and then ended up finishing. I was much happier fetching shingles and flinging them onto the roof for her than I was nailing them down myself.
Here I am, putting the ridge on. As you can see, we used "architectural" shingles, to match our house. However, the ridge shingles for architectural roofs come in a box for like $60 and one box contains enough ridge shingles for three chicken coops. Too rich for our blood! Instead, we just got a pack of cheap 3-tabs from the same manufacturer* as our architectural shingles, and in the same color. Then we cut the 3-tabs into thirds, making them 1-tabs, and used those to lay down the ridge. (I dunno if that's kosher for a human dwelling, but the chickens don't seem to mind.)
Both top rows of architectural shingles bend over the peak, and so do both top rows of tar paper underlayment, so even with a "cheap" 3-tab ridge it's gonna be real hard for water to find it's way in through 6 layers.
Even though we only bought 1 pack, we still have a ton of leftover 3-tabs, so there's plenty to re-ridge after 20 years when this ridge fails.
We also got the rest of the sheathing on. Lemontree will cut in a window on this side later.
* The shingle manufacturer, if you're curious, is Owens Corning. We got that kind because that's the kind Lowes carries, and Lowes is the closest place to our house. (We selected Certainteed shingles for our real house, because they seem to be the best and that's what the roofer with the cool German accent uses.) If the Owens Corning turns out to be trash, oh well, it's just a chicken coop. And since the coop was roofed by amateurs anyway, any failures are more likely to be due to the installers rather than the product used.