This is an anecdotal observation, not a scientific study, but I notice that my worms do not seem to eat worm chow- or at least, they don't eat much of it. I don't use it, or try to use it much except for fattening worms for fishing bait. Those worms are in different bins with different bedding than the rest of my worms so guessing that they don't have much choice other than to eat the worm chow.
Now that my herd is increasing exponentially I am scrambling to feed them all until the Spring thaw when I can access my outdoor compost piles again. I am feeding manure, and the bedding mix contains coffee grounds and spent tea bags but I want to make sure that all of the worms have access to as much food as they could possibly need so I started adding in a tiny amount of worm chow to the bins. For the most part the worms are ignoring it.
I can only surmise that they have plenty of other stuff to eat and prefer that to the worm chow.
Has anyone else noticed their worms refusing the worm chow, or do I just have a bunch of outliers?