Very upset. I have had three 5 month old pullets die this week. They went from seemingly healthy bird to dead bird in 12 hours. The first one past away 15 minutes after I let her out in the AM. Looked perfectly healthy the night before. When she came out of her coop she looked lethargic, had a lightened comb and dropped tail. I went to let the babies out and when I came back she was dead. Never seen anything like that. Four days later, another pullet was acting weird. Comb color was good, but she too had a dropped tail and head, puffed feathers and had no interest in the fresh corn I was passing out oh and she kept backing up. I thought she was egg bound so I gave her a warm bath per another forum recommendations. By night fall, she was dead. Still thinking my girls were egg bound, I hoped all would be well with the rest of the flock. Four days later, three birds exhibited the same conditions. By am (today) one was dead, one had recovered and one was still looking lethargic but better. I have 120 birds of various breeds (20) and only the pearl white leghorns are getting sick. They are also the only ones laying eggs. I called a chicken pro for advice and he thinks they may have started laying eggs too early (3.5 months) and are getting egg bound. I had left the light on in the corridor during the night which may have encourage the early egg productions. He told me I should always try to delay egg production for few egg bounding issues down the road. Would love to hear others thoughts on this. I sent the one who died today to UC Davis for Necropsy. Will have the results in 2 weeks. Here is a little background of my chickens that passed. They were purchased from Mcmurray Hatchery. Hatch date 3/17/10. They were vaccinated for Mareks. At 10 weeks, one of my chickens died of what seemed like Mareks. No Necropsy was performed, but she exhibited all the symptoms (blindness and paralysis). I called McMurray and they said 1 in 1000 can get the disease from the vaccination. Of the 230 chickens purchased that was my only casualty in the past 5 months. I sold approx 100 chickens and still have 130. All have been extremely healthy with no problems. The chickens live in 16 by 16 horse stalls with a 25 by 100 foot run. They are locked in at night. They were fed medicated chick started and were switched to Layena when the Leghorns started laying eggs at 3.5 months (19 weeks). I briefly swiched them to Calf Mana Brand Egg Maker three weeks ago when the store was out of Layena. Egg Maker smelled really strong (as calf mana always does )and gave them the runs. I switched back two weeks later to Layena. I now have a supply of egg maker and I am not sure if I should feed it up or throw it out. One of the ranch hands threw a bunch of moldy bread in the pen. I pulled it out as soon as I found it, but I assume that ate some before it was discovered. The auto water drips causing a very small muddy spot near the waterer. I have not resolved the issue cuz I can tell the girls love digging in the mud there. Not sure if the mud can make them sick. Beside the change in food, moldy bread and muddy hole, all else has remained the same for the past 5 months. Love to hear other peoples thoughts on issue.