What sort of numbers are you talking about?
Sprouted grains/peas etc have a higher protein content and are better nutritionally than dried grains.
I breed crickets on a small scale to feed to my birds and fish, they will breed away quite happily somewhere warm in large container just fed on grass and water and they will eat virtually any waste food you give them.
They are free protein and you literally can breed as many as you need.
In the summer months i always have some maggots on the go, you just need an old fish head in a flower pot in the corner of the garden and they will just appear.
Again, free protein.
Got a mature compost heap? dig it over and there should be hundreds of worms around.
I also keep beehives, and I see the odd bee getting taken!
