This may be a long post but I would appreciate all the help I can get! I graduated with a Bachelors of Animal Science last year and decided to start my own flock again after having to give all my 4-H birds away while I was at college. I went to a trade show in OH and bought 3 lovely birds who were together for about 6 months with no issues what so ever. I had some funny Brahma chicks also come in who died shortly after arriving for seemingly no reason. I figured they were sick already from the farmer I go them from. But they were never around my 3 hens. A few months later I got a rooster from a friend. Well he ended up getting sick. Coughing, ruffled feathers, Sneezing, and droopy wings. I thought he was going to kick the bucket, but he survived when put under a heat lamp and given electrolytes. No hens got sick and he was always separate from them. This spring I put the rooster, my old hens, and 12 new pullets (raised from chicks) all together with no health issues at all. This summer I was lucky enough to get 20 more chickens and my dad and I built a large chicken coop to hold them. The 20 Ameracauna chickens were free rangers who I had raised on grass since day old chicks,while the 16 original birds were in a smaller coop right in the middle of their free-ranging zone. About 3 weeks ago we put all the birds together and they were doing great until 5 days ago. Six days ago I noticed a large louse infection on a hen and decided to dust with Diatomaceous Earth. Tons of individuals liked it when I read it online and my usual dust was out of stock at my local feed store, so I decided to buy it. I sprinkled about 2 pound sin my 20' x 20' coop, just on the inside. The next day I came out (5 days ago) and found 3 hens with massive swollen eyes and nasal drainage only on half of their face. I sprayed Vetricyn fearing an eye worm (I didnt have eye anthelminics on hand) and added electrolytes to their water. These symptoms have progressed to each of the 20 new birds now showing eye swelling, nasal discharge, and loss of pigmentation in the face. Every day a new bird showed symptoms, while the birds I had treated with Vetricyn had no swelling, or eye and nasal discharge, just pale faces and combs. There is no smell to the birds and no coughing or sneezing. They are on a complete diet of lay crumble with oyster shell and a "flock block." The only other symptoms I have noticed are, I had one older hen go broody and suddenly all the older hens have stopped laying and have white feathers sprouting above their eyes in their dark brown feathers and the younger hens are around 5 months old and should be getting ready to start laying, but haven't yet (not even a fart egg!). IN addition, when I did incubate chicks only about 25% actually hatched. (2 hatches worth of 25 eggs each) The other 60% that were viable to lockdown died during lockdown. (The rest were infertile).I am not sure if any disease causes any of these issues, but I figured I would throw it out there. The 25% lived and are extremely healthy. No health issues from them have ever been seen in their 5 months of life. My local Veterinarians have refused to look at the birds since they don't do "bird" procedures, so I would love to get some opinions from you lovely folks. Does this sound familiar to you from past experiences with Diametous Earth intolerance, CRD or Coryza or worm infestations? No diagnosis seems quite right to me, and I have never heard of anyone in my area with these problems and if their was a "carrier" bird in my original flock, why did none of the other pullets show signs? And I got all the chicks from feed stores which I would assume are from a NPIP program. It just seems crazy that I get my Bachelors in somethin gI love and suddenly have this happen.