I am still on my first year of chickens and now my flock, all hatched the same week in mid-July 2016, are about 39 weeks old - or around 9 months old. These are all Buff Orpingtons. I have 7 hens and 1 rooster. The have a 4'x8' coop attached to a 10'x18' fenced run and are alloted several hours a week to free range (about 18-24 hours a week) I take meticulous care of them, including weighing them every month to track growth rate, largest hen, etc. So I just gave them their April weigh-in and every single bird has lost weight!!!!! My Rooster is back down to his weight just after New Year's!. All of the hens are below their March weight, some are below their February weight!!! There has been no change in feed. The exact same amount of food is available to them now as has been since they started laying eggs. Water = same. They free range for about the same amount of hours as they have been for a while. No new medications introduced as I am keeping them away from those. It has gotten warmer but I don't know why I should expect that. Egg production has been a steady 6 eggs a day since Valentine's Day. The ONLY DIFFERENCE in the flock from last month to this is that one of the hens went Broody and is day-in day-out sitting in a nesting waiting on a few golf balls to hatch. Any comments or advice welcome. Thank you in advance.