I'm switching them over now so I'll know more in the coming months. Right now they are 50/50 duckweed/sprouts and commercial chick feed. They seem to like it more than the commercial feed though. They eat a lot more of it than I expected though.
I found out they dont like chia sprouts or buckwheat sprouts. Kale and alfalfa sprouts seem to be favorites.
I have 14 (mostly very young) hens and get about 70 eggs per week. Your 40-for-100 does seem off like QJ said. In fact, if QJ is any guide, my ratio is a little low.