I purchased two Buff Orpington's last year from McMurray Hatchery. They were healthy and started laying several months later as normal. Upon their year of age I decided to get two more chicken's (4 week old Black Australorps). I was aware of quarantine and kept them at first in a large dog crate and then moved them into a new coop next to the old one outside (with my two year old Orpingtons) after a week. I still planned to keep them separate for at least 4 weeks. I thought that as long as they did not have contact and where at least 5 feet apart that they could not spread anything. One morning I came to check for eggs and let out the older girls and my one (best layer Marigold) had died in the nesting box.
I was shocked and saddened by this as her sister Petunia was alive and seemed fine. I did a ton of research about the possible cause and learned that keeping them separated but still within close air space might have still caused a contamination. I have waited 4 days now to see if Petunia would die to and that this would confirm a contamination was the result of Marigold's death. Any thoughts on this? Many forums said it is possible if could have been an egg stroke or just a fluke death.
Thanks for your advice,

Thanks for your advice,