Great question Ben.
When that shot was taken, we were just beginning to establish grazing infrastructure (perimeter
fence, pipeline, waterers, etc) and we hadn't scaled up livestock yet. We're still underutilizing existing forage. (Anyone want to lend some permies $200k for a badass herd of cattle?) With no infrastructure to graze everything, it's OK to
sell hay. Some of it was stockpiled for future mulch, some of it was immediately raked as mulch.
You can always run high stocking rates and bring fertility right back in from offsite by buying in hay and bale grazing or unrolling bales in the field. It made sense for us at the time, and I stand by the decision.
The only hay I'd buy in is from a place and person I know as clean, chemical-free hay.
Stockpiled forage - I'm in zone 5b. Stockpiling does work, but depending on the weather and snow loads I think most producers this far north still
feed hay for a month or two.