It's an interesting point of view. What is often said (about foxes at least) is that once a predator knows the chickens are there, it'll keep coming back till it's had them all, so you'd lose the whole flock anyway, but to predation rather than sickness. And that was my experience for the first 2 flocks, the first predated from trees at night, the second from the garden during the day. But the last fox attack here was May 2020; a neighbour with semi-free range production hens is still losing birds to foxes, so they're still around, but they're not bothering with us, even when, as a few nights back, someone(s) sleep(s) out. 5 roos on the premises no doubt has something to do with that, but I'm not sure I want to experiment with more sleeping out, even if there are more tree huggers amongst the youngsters (Amadeo has already shown his inclinations in that regard).
Do you plan to leave the pop door between coop and run open, or closed?
Have you noticed any temperature difference? Maybe that as well as the lack of mites is encouraging them to break the habit of a lifetime and roost in the new coop. Thankfully it's cooler here on the coast, max of 30 C expected today.