spring chicks quit laying 2 wks ago after laying for 6 wks

[Carolyn]

My grandson has 4 H hens who started laying about 6 wks ago, he was getting approx 12 eggs/day from 24 hens. Not as many as I thought he should get but still okay. He just got him some customers and was selling eggs. 2 wks ago they quit laying. They are in a chicken tractor with a pen that is moved over the site of last summers garden. Two wks ago a friend gave him some osyter shell calcium and grit and told him he needed to feed this in addition to his laying pellets. About the same time DGS put hay in the nesting boxes which they formed into a nice little nest and layed one egg in it. No eggs since. They are not sick. He feeds them daily and they consume most of the food in a 1 day period. Mine are laying 2-3 eggs less per week so I don't see how weather or lighting could be the cause.

Any suggestions? He is getting pretty discouraged and I think Dad is more like disgusted. They have a nice chicken house.