Well let me ask you some questions if I may.
1. Where did you get your birds? Some breeds or lines of breeds are inbred and have problems.
A. None are hatchery birds. All are from Featherz, Happyhensny and a breeder in New Rochelle, NY
2. What breeds do you have?
A. Shorter to say what breeds i don't have. LOL I have Ameruacanas, Olive Eggers, Maran, RIR, D'uccles, and a few "barnyard, who's your momma" birds.
3. What and how much are you feeding them? Chickens need a balanced diet. To many treats or non feed things can throw things off. I have BR's that don't lay well but also aren't eating the commericial feed as much since they are free ranged and not in the coop.
A.They have access to Grower/Finisher 24/7 and calcium on the side (I have babies in both coops. grrr) Will put them back on layer when the babies are 8 weeks (young for the babies, but I don't see them helping themselves to the oyster shell that much)
4. Any stressors? Like me, chickens don't produce well when they are upset. I've found some breeds don't get along. I gave away my Aussies and GLW's cuz they were picked bald. My birds do NOT like strangers. This includes family members who are not around them alot. DW got flogged by a rooster who lets me reach down and touch him. Never let the kids chase your birds or stress them by grabbing them. Mine freak out when the neighbors cat walks through the area. They now have two yippie dogs. Very annoying.
A.Not much stress....very very occational young girls who like to pet them, but basically they are their own stressor. Crowded conditions in run, so I let them out daily for the past 2 weeks, all day from 7 am til they lock the coop door at night. (hehe....I wish they would lock up when they go inside.)
5. Free ranged or confined? Some breeds don't like to be confined. How much space they have to roam does make a difference.
A.Ironically, the small side is cooped all day and I am getting more eggs from those 6 hens than the 11 in the large side that are out all day. Go figure.
If anything the configuration of birds changes more regularly than I would like. First I have all adults, then the Sumantras move in as juvies, then a coon wounds one of the D'uccles, so she is put in a rabbit coop on top of the broody area, then the eggs hatch and the babies run around. All since April. I left out moving the D'uccles out of that coop to a coop of their own when a second set of Juvies when outside.
Hope this helps.