I have about 250 laying hens (ages half 1yo and the other half 2yo) and 125 one month old chicks. I'm use to loosing hens here and there without knowing the cause. It happens. However, I've been loosing up to 5 hens a week over the past month (of both age groups). Sometimes 2-3/day. They all look healthy. No parasites that I could see. The coop is cleaned weekly with fresh pine chips. I've disected a number of them. No foreign objects, no impacted crops, none have been egg bound and no ascitites. No change in diet and, knock on wood, no chicks have died. They all have access to food grade DE and I see them dusting regularly. I'm stumped. Any ideas?