OK, gosh, now I'm back on-board for field peas! First I was all set to feed peas, then I was scared of this newly-discovered Trypsin stuff, and now I'm convinced that it's more of a risk in some beans than it is in peas. In just 48 hours since I first posted, I have learned a lot and changed my mind a couple of times.
The pattern that seems to be emerging is that some legumes are higher in Trypsin than others. I would guess that clover and birdsfoot trefoil (which are both legumes) aren't too high in it, because our pasture is loaded with both of them.
However, I am also excited to discover that turnips have such high protein. I probably should have been aware of that, because folks around here plant it for cattle forage, but I just never made the connection. Also, they can be early spring planted (along with the peas) which puts me on-track for mid-summer use.
So, to recap, here's what I'm thinking right now: peas, turnips, millet, buckwheat. I'll still be feeding some wheat berries that are grown nearby, and I'll have a feeder full of high-protein all-purpose pellet feed in the tractor, so the birds aren't totally reliant on the forage I plant. I'll be planting each thing in long, narrow parallel strips, so I'll be able to move the tractor down the strip, and it will straddle all of the plantings, giving the chickens a "salad bar." I'll plant the peas and turnips in March (or, depending on mud, as soon thereafter as I can get them in) and I'll get a parallel planting of millet and buckwheat as soon as risk of frost has passed. In my past experience, white proso millet will set seed in about 60 days.