Hi, I've been lurking here for many months trying to figure out if I can possibly fit a few chickens into my tiny beach city lot. But I saw your post and just had to join because, heck...
Never mind that I'm currently a city girl, I run a bustling sailing program out of a teeny 1910 building

cough:
shack :cough

, I garden and have many fruit trees on a tiny beach city lot, and I know how to pack a sailboat for an extended ocean cruise. Figuring out how to get the most use out of any given space is something I am good at!
So here is what I came up with for your lovely barn (wow, do I ever envy the land you folks have in the country). I think with your winters your chickens will have to spend considerable time indoors so I figured you should have oversized breeding pens. I doubted you would ever need all five of those shelves as brooder pens (unles you have silkies
), so I thought maybe remove two and the remaining three could be easily be configured to switch between brooder, broody pen, and hospital as needed. Plus one 4 x 5 shelf is big enough to subdivide into a couple broody pens if needed.