Thanks for your idea and the responses from the others, something does need to change to trigger a resolution.
To split up the barn would be horrendous for me trying to service each area climbing over dividers with food and water hoses considering the long rectangle shape. In theory it sounds workable, but in practicality my arthritic knees would falter.
But your idea sparked another. After two weeks of being in the barn, and now just yesterday morning losing another 7 in a heap, I decided to 'go for it' and clean the chicken house, creating a change in routine for the birds. The windows were opened up about 12" for air for me. Happily there were no hidden dead birds in the mix. I forced all the birds out of their favorite mounding area, rearranged all their roost setups and stirred the birds up the entire time the landscape pots were dragged around collecting the old bedding from the floor.
They tried to mound in a new corner, perhaps just to get far away from me? Some had settled down to nest by the open windows, showing the temps were not a problem. Only 6-8 ended up under the heat lamps out of the 70 or so that are there. The temp under the lamp is at 75, varies through the rest of the barn since it is not insulated. Now they were far more evenly scattered in the house, some at the feeders, some at the water. These birds are feathered so they were fine.
Maybe 5 were on roosts. None of them tried to approach the exit door, for a couple of minutes a few tried to fly around testing their wings... both things expected with a flock this age. Prior flocks would have the tops of the water and feeders scoped out to land on, never happened with this group. They hang on the floor. On the plus side they will not be ones to need a winged clip being an escape artist going over a fence.
Holding my breath to see what's there today. Basically they have a strong mind set.
They have been analyzed by the State doctor for physical problems... if necessary I'll sacrifice one or two more to have them tested again hoping something has surfaced. The ones with the death wish might just cancel themselves out with normal, even if only a few, birds remaining. This problem would have been a lot worse if my flock was larger, so there is that to be thankful for also. Basically, it is what it is.
Again, thanks for the suggestion... much appreciated!