Your chickens start inside or somewhere they can have the light on them. The first week the temperature for them should be around 100 degrees. Each week you lower the temperature by 5 degrees till the temperature matches the outside temperature then you can move them outside. They should also be fully feathered.
If you let them free range without supervision, you are going to find out the predators will pick them off until you have none. Chickens can't do much to protect themselves, they have to fly or hide if possible.
Hello and Welcome To BYC! Time to start building the coop now, depending on the weather, most people put their chicks outside at about six weeks when they are fully feathered and don't need extra heat anymore. As mentioned,if you let them roam, you will lose some to predators sooner or later, most people have a secure coop and run because of that.
you might like to check out the BYC Learning Center, lots of good articles on all aspects of chicken keeping. https://www.backyardchickens.com/atype/1/Learning_Center