What is a one-sentence summary of the following article?
There are 3 main types of chicken feed: layer pellets, which are high in calcium and given to egg-laying hens; finisher feed, which is high in protein and give to meat chickens over 6 weeks old; and standard chicken feed that can be given to chickens in general.  Food for standard-size chickens usually comes in pellet form, while food for smaller bantams often comes in crumbles. Keep the food fresh and clean. During the night, cover the food container and feed up with a lid to stop it from attracting pests, and clean up any leftovers so that they don’t turn moldy. Provide grit to help your chickens grind down their food and provide calcium for laying hens. Crushed oyster shells or egg shells are a great source of calcium. Free-range chickens may not need to be supplied with as much grit, as they find things in the ground to replace it.  Many chicken feeds already contain calcium-rich grit. If not, you can buy it separately at the feed store and add it (according to the ratio provided on the package) to the feed. Additionally, you should let your chickens free-feed on insoluble granite grit 2-3 times per month. You can buy this at the feed store as well. Chickens can eat a wide range of foods, such as vegetables, fruits, table scraps, bugs, seeds, etc. Make chicken feed the staple of their diet, though.  Never feed your chickens avocado, rhubarb, onion, garlic, uncooked potato or egg, citrus fruits, alcohol, chocolate, or anything salty. Don’t try to get rid of rotten food by giving it to your chickens either—fresh food is always best. Table scraps and other treats should make up no more than 10% of a chicken's diet. You should provide 1 gallon (3.8 L) of water for up to 3 or 4 chickens, and increase the amount based on additional chickens. Always make sure the water is fresh and clean, and remember to refill and clean the water container daily to prevent a build-up of bacteria.

Summary:
Choose the correct type of chicken feed. Supplement your chickens’ diet with high-calcium grit. Give your chickens limited treats. Provide fresh water for your chickens at all times.