I am not the least bit scientific about my sprouting. I've done enough reading to know that the sprouting process breaks down the antinutrients in the grains, making the nutrients in them more bioavailable than the nutrient in the seed from which the sprout came from. Sprouts are more nutritious than fodder. I consider a seed to be at the sprout stage before the roots have developed past the single tap root that comes out of the seed, and when the only leaves present are the sheath in the case of a monocot, or the cotyledons in the case of a dicot. After the blade of grass exits the sheath, or the true leaves appear, or the root starts to branch out, I consider the sprout to have grown to the fodder stage. I like to feed them before that point. A day before I plan to feed them, I put the jar in a window sill, so the sprouts will green up.
I do not consider sprouts to be a substitute for a balanced chicken feed. What I do consider is that the sprouts are an easy and cheap source of green vegetable matter at this time of the year. My ground stays frozen almost 6 months of the year, snow cover 5 months and fresh greens are obviously lacking since the snow is up to my knees!
I like to give them a qt of sprouts/day. I have 29 birds. They would obviously eat more, but this is an easy amount for me to grow.
Sprouting also allows me to feed my need to grow things! Alfalfa and brassica sprouts are great on salads, and lentil sprouts are great in a salad or stir fry.