We have been raising birds for 2 years and up until Friday, we had never lost one. However, on Thursday 2 of our 16 week old pullets (a Polish Tolbunt and an Olive Egger) went from seeming perfectly healthy to declining and dying in the course of 24 hours. The birds were lethargic and both of them had weakness in the left side of their body. The left leg was balled up and pulled close to the chest. We have 2 more 16 week old pullets and one of them may be getting sick as well. (I'm at work, my boyfriend called me and told me she seemed less lively than normal this morning.) I have no experience in chicken illnesses so I'm at a loss. Last week we extended the chicken's run and moved them into a larger coop. I don't know if the move could have triggered it? There is nothing toxic in the new coop that they could have gotten into, BUT when we extended the run I raked the whole thing out and I could have easily kicked up bacteria from old chicken manure. Does anyone have any thoughts? We're very worried.