I had a flock of 21 laying hens and one rooster. I went to an auction and bought a mess of extra pullets. I do not recommend this since I have had nothing but problems ever since. The established flock was about a year old and I to this day have had no problems with them. The pullets I brought in were quarantined for one month prior to integration. This was the beginning of October. Since then I have had to cull one about every 2 weeks. The symptomatology is the same for all birds. They quit eating, get withdrawn, then start drinking and passing large amounts of urine. Then they limp...eventually lay down and die. I can't imagine it's viral or bacterial since they are getting affected one by one slowly. Roosters appear to be immune. They have a large coop and run with pine shavings rotated and cleaned every 3 months. Waterers and feeders are cleaned and disinfected about twice a week. I have tried ACV, although I can't find organic where I live so it's just regular. I have wormed them and tried antibiotics (injectable) in different cases, but nothing works. The stuff progresses slowly... from onset to death is about 2-3 weeks and they are never sick together...it's one by one. They are on Layena and scratch... some have started to lay.... most haven't by the time I cull them. As soon as symptoms present the sick bird is isolated. Does anyone have any ideas? Any thoughts would be appreciated.