80 fresh earthworms like red wigglers size (about 3 inches long) make up just 4% of the protien for a laying hen. i think your chicks can eat as many as they may want... Chicks and pullets need more protein than do laying hens.
Chickens, All ages, Love worms. I think they know when to stop. Just try to make sure everyone gets some, not just the fast ones! Though some earth and inch worms contain parasites, i think you are safe! My girls have never had a problem with earthworms!