There's a long thread on the forum on sprouting, if you want to do a search for it. There are some threads on wheat grass, too.
For large amounts of sprouts for a flock, people usually use 5 gallon buckets or big bags to sprout in. I've never used a bag, but you just hang the woven bag on a hook to drain, after soaking or rinsing.
For the buckets, you just use a pair of buckets that nest inside each other. The one on top needs to have holes drilled in the bottom. That one is where you put the seed. The bottom one holds water. You just set the bucket with the seed into the bucket with the water, to do the soak or a rinse. When you want to drain it, you take it out. I dump the water out of the bottom bucket then.
For wheat grass, you can also use garden flats to grow it. I have flats with drain holes and flats without drain holes, that nest inside each other. I use landscape fabric to cover the bottom, for holes that are too big.
You can even just grow wheat grass in pots or flats, in dirt, if you want to cut it for them or just put the whole thing in the coop or run.