You will be feeding them the "starter" feed until about this time and can then begin feeding "starter/grower"
You can can feed their chicks scraps, or worms and other bugs from the garden... Small amounts of vegetable/dairy also bugs and worms should be fine for the chicks (and they'll love it!).Just remember that starter feeds contain everything chicks need to survive and thrive, and filling them up with too much of the "other stuff" can throw off their nutritional balance.
And give them as much feed as they want. They will eat as much as they need, and come back later for more. They are good at self-regulating their feed, unlike a dog is.
Chickens do not have "teeth" so they need grit. When they free range, they will find their grit. If they are contained, you will need to provide the grit. For baby chicks, sand, parakeet gravel or canary gravel, available at your local pet store or grocery store pet aisle.
When the weather is warm enough, and sunny, they can venture outside. Put them in a wire cage or erect some other temporary housing and place it in the sun, making sure they have access to water and shade if they need it. They'll absolutely love digging around in the grass. But don't leave them unattended! At this age they're good at flying and very susceptible to predators. Also, if it's windy they'll get cold - they'll let you know they're unhappy with their loud chirping.
By the time they are full grown, they will come when they are called, and stay pretty close to where you have their shelter and food. Make sure they have access to water at all times.
They don't really need much in the way of comforts. It is always nice to provide a chicken coop or they will lay their eggs anywhere they find a nice hiding spot. This type of chicken coop holds about 12 free-range chickens. They lay their eggs in the nest box and you don't even have to go inside to collect them. If you want to keep them contained with a small outdoor run, this coop will take care of about 6 chickens. Interested in starting a small flock? In general, you can have 3 hens (no rooster or crowing involved) and get 14 eggs a week! That's 2 eggs a day!
Our first set of chickens didn't have a coop the first year. They would roost in the trees. When we had a snow, the following morning, they would shake the snow off and fly out of the trees to the ground. The weather didn't phase them. This is our chicken coop now, you can see that they aren't afraid of a little snow!
Of course, during the winter you will have to provide food. They will scrounge around in the snow looking for tidbits - especially under bird feeders, but they need something of their own to keep their metabolism up and keep them warm. Your local feed store will have feed available for the winter.
Chickens will stick together. If you have a rooster, he will call to his hens to come and eat something special he might have found.