Thank you. The maximum span of the beams is 12' What is the spacing between the beams?
You can't use dimension lumber for this. Not even close. You need steel or a robust LVL. Which do you prefer?
The application, yes, but not this loading. Hay storage requires a 300 psf loading. It's a very heavy load.
You will need a 7" x 18" 2.0E LVL
Do you have any other questions for me on this topic? If you could rate my answer, I would appreciate it.