@@MurraysMutts I like it. Entire one piece Roof is salvageable and can be strengthened....(all the walls have to come out) care must be approached to shore up the broken left side of the main roof wall-truss. The way you work this is leave the roof where it is (do not try to bring the roof back to where it originally was located) and place beams nice and straight underneath.... adding new wall-beam-piers right side first...while monitoring left side...until entire right side has new beams. Leave back wall where it is. Then work left side jacking a shoring up with new beams. Once the two long sides of the barn has new beams (roof is safe, building is saved)...you can make determination on the remaining back wall....replace or leave as-is.
What i love about this building (for ease of fixing) are two things....1. they left out many of those long ceiling boards .... overhead ceiling truss never put in....you can install them to shore up the roof during jacking to support the two roofs together. 2. there's space to run new boards under those slightly rotten roof trust ends....extra rock solid support.
You are storing hay in their now....it's still a viable building...because the roof is still good.