We have swath grazed straight barley, but usually use a mix of oats/barley/rye, and are working with some triticale this year.  The light grain is probably better for cows as they won't get too much energy.  I would have at it.  Cheap feed is a great thing, just leave them long enough they have to clean it up.  Some cross fencing is definitely time well spent.  We use portable rolls and rebar posts.  Pound in with a little sledge and pull out with a little pipe wrench (twist and pull).

May be a bit more shelling with more mature barley but the geese will take care of that.  We sometimes like more mature as it will often sprout in the spring and make for super may/june grazing (although I doubt your grainfarming neighbour would see that as a bonus).

Obviously price has to be right, but it works.