That's not true. You can switch feed anytime you like. Why wait until next year? The only issue switching feed is if it's a different texture - crumble vs. pellets. Not all chickens like pellets and may refuse to eat them. And they are too big for young chicks. If it's all crumble though, it doesn't matter. The chickens may or may not notice you switched at all. If they notice, they may be picky for a while but they'll get over it. If you want protection against Coccidiosis, switch them to medicated feed now.I know it is not good to switch feed once it is started and mine is non-medicated, the other feed from tsc is 4 dollars cheaper I will use this next year