If you plan on getting a rooster or two, be aware that they are a LOT louder than you think they are, and they don't just crow when the sun comes up. My boys start crowing at 3 in the morning until about 8am, and then they will start crowing again at 3 in the afternoon when I usually let them out for their daily run around the garden. If you have neighbors close by then roosters may not be a great idea, not everyone is deaf like my neighbor.
If your bird is sick and needs to go to a vet then make sure you do your research first!! A lot of your everyday vets will not know much about chicken diseases (unless you live in a more rural area), and you'll be charged a huge consultation fee and get very little information and possibly a bad treatment suggestion. If you live in a suburban area then your best bet will likely be a vet clinic that specializes in exotic animals, but it may cost you a bit more. Medication for chickens is often also very expensive because they usually require high dosages, often equivalent to what a medium sized dog would need!
Regular checks of the underwing and vent area will usually tell you if your birds have mites and checks of the feet are good for picking up leg mites and bumblefoot if your birds spend time walking around a rocky yard.
If your bird is looking under the weather then apple cider vinegar and garlic in the water is often good at clearing out nasties. Feeding your birds eggs is also good for giving them back a lot of nutrients.
Avoid overdoing it with the treats, no matter how hard it is to deny your birds when they're pulling the old puppy dog eyes. Dairy and other foods they generally wouldn't have access to in the wild can cause stomach upsets!
And the most important advice I can offer - make sure to give your birds all the kisses and cuddles they could ever need, petting chickens releases the happy hormone in humans, so it's beneficial for us all to snuggle our chooks!
