Take coffee grounds for example... I drink my java, dump the coffee grounds onto a plate or pan to be dried, the grounds are then "fed" to my red worms or they go into the big outside composter for the earthworms, and they use it as fuel to make castings which is worked into the soil for nutrients to grow more things.
The coffee when brewed is typically acidic, but because the acid is water soluble, most of it is removed in the brewing process. The pH balance of the grounds is closer to neutral and therefore fine to use with your redworms. In fact, it's a good source of nitrogen for them. And they love it!
Egg shells are another example. Lately I've started saving some of my egg shells and drying them in my Excalibur dehydrator for a couple of hours (along with the coffee grounds to dry them out).
Next, I put them in a plastic bag and use a rolling pin to crush them up as fine as I can.
These are then sprinkled over the contents in the composter and the worms process it like the coffee grounds. The calcium from the shells provides nutrients, but also acts as a buffer if conditions in the bin are getting too acidic. Supposedly it also helps in reproduction for the red worms. Eventually it gets converted to castings and goes into the garden.
The chickens get nourishment from things in the soil, either plants or insects, I eat the eggs the chickens produce, the shells from the eggs go to nourish the worms, and the worms create more nourishment for the soil.
It's a beautiful world.
And now you have two new treats to feed your red worms!