I'm sooooo new at this, but what I read seems to point me in two directions with the sprouts, and so far, I notice the chickens seem to notice.
1. Grain. Sprouted 3-5 days, until the seeds have basically "unpacked" all the chemicals nature provided to feed the plant embryo, but BEFORE the plant starts to send the shoots up vertically. No green, in other words. The sprouts haven't formed a mat yet, and you're still feeding grans. It's like you're making the grains easier to digest for the chickens.
2. Green. Sprouted 6-9 days, until the seeds have formed the mat, have sent up lots of green shoots, and basically look like alfalfa sprouts. The seeds have used the "unpacked" embryonic growth chemicals, and are actually young tender greens. Different nutrients are available at this point. It's like you're giving the chickens good green feed along with some healthy root structures.
If I feed the sprouted grains, the chickens just tear into them. If I feed the green sprouts, it takes them longer, but they still eat it all.
I do both, so the chickens are getting the benefits of both.
FWIW, I could be completely wrong on all this!
Richard in Neenach, California