It's not just Tractor Supply and it's not just that brand. My chickens stopped laying and I haven't been inside TS for months. We changed their feed and within a day or two they were laying like crazy again and obviously feeling better. They were never vaccinated. They were never fed cheap feed. They were never fed anything with less protein. BTW, I've been seeing experienced chicken people talking about their hens not laying for a couple of months. I've seen at least three brands cited.