In the last two days, both of my Brahma pullets have died, so I'm trying to figure out what happened and what I need to do to prevent it from happening again. I have 4 laying hens, a tiny little Serama rooster, a big Black Australorp rooster, 2 adolescent hens (~4-5 months old), and 2 8wk old pullets (4 counting the Brahmas). They all free range in a half acre fenced portion of my yard and get locked in their coop overnight. Yesterday afternoon, I fed all my chickens some hard boiled eggs and just sat and hung out with them for a little while. At that time, everybody seemed happy and healthy. An hour or two later, I noticed one of the Brahmas standing by herself. The two usually wander off to some distant corner of the yard by themselves, so it wasn't odd for her to be away from the flock, but it was odd for her to be alone. I started looking around and found her sister laying dead in the middle of the yard. I couldn't find anything outwardly wrong with her, so I did a necropsy (gross, I know, but I'm a vet student and had a general idea of what to look for). As far as I could see, she was perfectly normal. About two weeks ago, I guess my big roo hit puberty and started trying to mate with everything in site. I could hear a lot of commotion inside the coop after they got locked up in the evenings, and had seen him chase down some of the adolescent hens pretty forcefully. Within a couple days of this starting, I found a couple 6wk old pullets dead in the coop. I assumed that the roo had gotten too rough with them, so I started locking him up in a separate cage at night and everything had been fine since. I continued to let him free range with the hens during the day, because the older hens seemed to be able to handle him, and the younger hens quickly learned to stay out of his way. However, my first suspicion was that maybe he had caught this Brahma and been too rough with her. So, I locked everybody up as usual last night, and this morning found the other Brahma dead. I know it wasn't the roo, or any other predator, since they had been safely in the coop all night. This one also looked completely normal, no marks on her anywhere. Everybody else still seemed happy and healthy this morning. Since these two were always together and usually wander away from the rest of the flock, I'm wondering if they could have gotten into something poisonous together? These were two of my favorite babies, and they were just starting to look like real chickens instead of fuzzy, awkward teenagers Any ideas about what could have caused this would be appreciated!