I was thinking the same thing. These feeds are cheapest for reason, they meet the bare minimum on a good day so what are they swapping out to keep cost down. Just like any other animal feed you get what you pay for.I get the many are complaining & there may very well be a problem with the feed. How many are newer chicken people who haven't gone thru a winter with older chickens? How many notice like here in SE PA we have had many more cloudy days than normal? Things on the net spread like wildfire & conspiracy theories abound. Aren't those feeds cheaper because they lack things like probiotics & such? Feed is cheaper for a reason. Has TSC ever been approached & asked for an explanation? Just because many have the problem, it doesn't mean it's the feed, but then it may be the feed!
At least in my area TSC is the worst for finding fresh feed. So if the bag of feed you bought is old or the manufacturer used aged products to produce product to keep cost down it’s going to decrease the nutrition available.
The weather has been unusual all over the country. I saw a lot of post with people experiencing usual winter weather for their area. Flocks not use to below freezing temperatures all of sudden getting them is enough stress to stop laying.
So even if someone says nothing else has changed but the brand of feed, there might be enough smaller stresses that we aren’t seeing that is effecting them.