SO - I figure that if I retrofit these for Dutch doors, I won't be looking to split it precisely at the middle, but more where it makes sense for the door.
There's that crossbar on the inside of each door. So - what I'd plan to do is for the cut to be just above that crossbar, and I'd hammer in a new crossbar right above where I was going to put the cut, and cut between them. I'd also put in a new hinge, so that each half of the door had two hinges, and a new latch, so each half would have one latch.
See anything wrong with that plan?
This won't be "soon" - first priority is getting the rest of the apron staplegunned down, and sod stapled down. Then we got a new big gazebo that's going to go just west of the run, and we need to put the waterproofing/UV proofing on the cover, that's going to make spending time outside with the girls much nicer for us sun-sensitive types. Then there's figuring out how to hang a stick swing for the girls in their run, and put a roost in there somewhere, and getting the CORRECT pvc pieces to make a no-waste feeder and a matching waterer for them, and curtains for the nesting boxes.... honestly, it's not the numbers of the chickens that keep going up, it's the numbers of things I need to do.