Chickens LOVE maggots, High protein, you virtually make them out of thin air, and they make for great eggs. Kill a mongoose, rooster, politician, whatever, and cut it in a few pieces and leave it out on a piece of plastic in the shade in a cage for a day or two for the flies to lay their eggs. Then roll it up in the plastic until the maggots hatch and get nice and fat, you will have to learn the timing of your local flies. Then feed the whole mess to the chickens. Chickens love meat and will happily eat mongoose or roosters.
For calcium for their eggs the oyster shells need to be crushed small enough so they can get it down, if you buy it in a store it is usually a good size. If you feed their egg shells back to them be sure to crush the shells well - if a hen finds out that eggshell is good to eat she will start eating her own eggs.
I haven't tried feeding anything having to do with fish to my chickens, but the hogs out out once and got into the trout food, which was made of fish meal. It was quite a while after that, several weeks, before the hogs were butchered and the meat tasted just like fish - the oils from the fish feed had gotten into their fat and meat and stayed. Completely inedible, even the dogs wouldn't eat much of the meat. Maybe one person experiment with feeding fish food to just a few chickens and see how that affects the flavor of the meat/eggs. The fish bones would be a good source of calcium for the egg shells.