it doesn't have to be measured just like for every 40 lb give them 4 lb of scraps I would say what you are giving is probably about 80%, it won't hurt them but when they are laying then they won't be as productive as birds that stick to the layer ration with no treats, but birds that get treats also lay darker yolks and are happier, so some are good but too much can't really hurt them but may make them less productive (and overweight which isn't god for them either), if you add soybean meal to their food(to boost protein) you can get away with feeding more scraps. The mineral grit is meant more of adults(if you post a picture of it we may be able to figure out what it is), you should be able to buy chick grit somewhere. My girls won't eat banana peels but they will eat the part we eat, and my girls will also eat all of the strawberry. As for the eggshells it is good to feed them back to the chickens after they have dried out, but you have to give them oyster shell to help them with calcium. as for the green peels you can give them all of the scraps but if they don't like it (or it isn't good for them) then they won't eat it.