Chickens, just like us, can get sick.  The easiest way to deal with this is to be proactive, not reactive.  If your chickens have good feed, clean water, and plenty of room, they should thrive. First off you should fine the best feed in town.  commercial feed offer everything a chicken needs.  This feed works, but you can do better. Most commercial feeds are mainly corn.  Corn is not a food that chicken would normally ever eat.  Try to find a local feed if you can.  Not only will it be better for the chickens, but it will be better for the environment and the local economy.  Water is externally important to chickens.  Make sure they always have access to clean water.  Keep the water about 6 inches off the ground to keep the chickens from kicking dirt into the water.  We recommend having 2 waterers for your flock.  You should be able to get away with filling them every week to week and a half.  Remember, make it easy.  Having 2 gives them more and makes less work for you.  Be sure to clean the waterers when you refill them.  People are always curious how much room to give their chickens.  My answer is always as much room as you can give them.  If you need them to be contained at all times you should try to give each chicken 8 square feet of outside space.  Once again, the more room and better feed you give the healthier and happier your chickens will be.