Did you ever contact the company or just assume it was the feed?I follow many homesteaders on you tube and FB. Many of them have experienced the same thing with TSC feeds. Some didn't want to believe what they suspected, but when they went to the process of elimination, quit feeding said feeds and started with things like table scraps, mixing their own, or finding a local feed mill their chickens started laying again. So this is not a conspiracy, it is a real thing. Several years back I was feeding PP from TS when I was in CA. We had 20 girls and they dropped off on laying when winter set in but then spring sprung and egg production was next to nothing. After doing some research, I switched to a local feed mills feed, and within a week the egg production increased significantly.
Since then I never went back to any of the big corporate stores for feed, always a local feed store and besides I like supporting local businesses, AND keeping my girls happy