At first, I was just using a strainer with relatively large holes, on the oyster shell we had for our chickens. This gave me small pieces for the quail and large pieces for the chickens, but it took quite a while to get a very small amount, so I went on to using a stone mortar to grind it before using the sieve to get rid of the large pieces. Very noisy and still a lot of work though, so I bought a cheap, small blender and started using that. I've only used it a couple of times, it's also quite noisy and it still takes a while to get a decent amount, but at least it doesn't require as much work as the other two. I'm not sure the blender will endure forever though, but for now that's how I do it.
I wouldn't bother putting them inside as long as long as predators can't get to them, but I don't think it's upsetting their light cycle unless you keep them shut inside a dark coop after sunrise. It might stress them to be picked up and moved to the coop though and stress can also reduce egg laying. Having more than one male in an enclosure can also cause stress.