Chickens Falling Sick At Same Time

About a month ago one of my red girls suffered from a swollen and distended uterus which stemmed from an infection. We got her to a vet too late and sadly my beautiful girl passed away. Now, about a month after her death, another one of my chickens was just taken to the vet and she also has a gynaecological issue, different to the first one. Her egg implanted itself into her abdomen and her body is now fighting an immune response to a foreign body. She may not make it but we are still crossing our fingers and praying. Just this morning I noticed another one of my chickens seemed a bit weak and out of it, I believe she may also be suffering from a gynaecological issue, I plan to rush her to the vet immediately. Each of my three girls were part of a flock of four who I took in 1 and a half years ago. In all my years or raising chickens I have never experienced gynaecological issues. Its only the girls from the same little flock who are having these problems, and all so close together. Is there a possibility that the supplier of these chickens could be at fault? As in, only the chickens we received from them are the ones experiencing similar issues all in a close time frame.