I bought most of the ingredients yesterday to mix up a batch of this to feed temporary "in-house" feeders (we buy them a few days before hand and want them to eat the bestet). My question is, eventually the cereals will get stale (since I'm not feeding very many ratters a week) and the mix makes up quite a bit. Will the stale food be bad for the ratters and/or will they eventually not want to eat it because it is stale?