just like you would do for alfalfa or mung bean sprouting in your kitchen - except on a big scale.
Of course you can get commercial sprouting kits for a lot of $$. I use what I have, trash cans, buckets "my favorite thrift store finds-rubermade storage tubs with no lids!"
I use rectangular rubermade storage tubs about 10 inches deep and the size of a bed pillow, some with drain slits cut into the bottom.
Put your seeds in a tub or bucket ( I put 2 heaping grain/feed scoops in a tub, so about 3 or 4 lbs probably)
Add 4 x as much water to soak, ( I will split this between 2 tubs or buckets as I don't want to lift 60 lbs of sloshing water and seed)
Soak for 6 to 12 hrs. ( I soak overnight)
Pour the soaked seed in containers with some drain holes in them, don't cover!!
They should not be sitting in standing water after the first soak!!They should begin to sprout in the next 24 hrs.
( the coolder the temp the slower they will sprout. I generally put my draining tubs in my spare bathroom shower stall in the winter- summer I put them in the barn, Low light!!.)
Rinse the sprouts daily,Make sure they drain well. ( This is why I like the rectangular tubs, it keeps the sead spread out about 2 " deep and it wont mold!!!
. Ater 3 to 5 days you have some big sprouts! you can feed this or even pour the sprouts into growing flats with soil and grow some "grassy" stuff in another 3 or 4 days, then you just pull it up like a sod roll and toss it out to feed.
I weighed the last 5 day sprouting. started with 3 lbs dry, ended up with 11 lbs sprouts-
I hear you can add all sorts of suppliments to this- I don't - it's not my only chicken feed, I have pasture and compost they feed off of too- worms and grubs... They hardly eat lay mash anymore, and the eggs are hard shelled and dark yolked.