Hello! We're still slightly new to the wonderful world of raising poultry. We love our girls. We have a rainbow flock, because I could never make up my mind of what breed I wanted. Currently we have Amerecauna's, New Hampshire Red, Wyanedotte's, and we had some barred rocks.. We have older hens 3 of them to be exact, who are our survivors from a previous attack or a neighbor dog almost 2 and half years ago now... so they're pets to us.. We will let them live out their natural lives... The barred rocks were approximately two and a half years old. Almost a year ago, we found one of the barred rocks just dead in the chicken coop. We were then down to three. Then one of the hens started acting REALLY weird... she wouldn't come out of the coop at all... she would sit on the eggs ALL day long... but peck and eat them... and was insanely mean to us, and the other chickens... she became super lethargic and we had to put her down, because the other chickens weren't laying. Then just this last week one of the barred rocks started walking around SUPER slow and puffed up.. wouldn't eat and wouldn't drink... we just kept our eye on her... the next day my husband found her dead in the chicken coop. Then just today I couldn't find our last surviving barred rock, then I found her in the chicken coop... I went to grab her, she went to get away and she fell over and couldn't walk.. She got up to walk again and just fell over.... So I had to put her down too.... We've lost three chickens... What gives?? Are my other chickens at risk? Was it their age?? Are barred rocks prone to this??? PLEASE HELP! Thank you!!!!!