I have been doing a ton of research to make sure I give my little Penny the best diet possible and avoid any complications or problems if needed. One thing I've seen suggested a lot is rotating proteins or formulas (I have also read this isn't necessary, but I've yet to find anything suggesting that it is detrimental to their health, so we don't need to argue about whether or not you need to do this). How often would you rotate, if you chose to, or if you do rotate, how often do you? Quarterly? Bi-annually?