The previously mentioned green eggs turned out to be being laid by Camilla, the Easter Egger. As mentioned, she laid her first few eggs in a shelter in the run, that I had added to give them shade. 

To encourage her to lay in the correct place (the nesting boxes inside), I removed those shady spots. But she didn’t accept that; instead she flew onto the roof of the coop (about 7’ up):

And instead laid in a spare compost bin just outside the run:

Sigh. I’ve had to let her back into the run several times, as the front of the roof is too high to which to fly. So I’m working on covering the run, so she won’t be able to get out.

In good news, we got a light brown egg from another chicken today… and it was correctly in the nesting box. I’m not sure who laid this egg, but at least she figured out the right place!