Can I make a suggestion? How about a pretend broody hen? I do it all the time...so do lots of others. I know it's a long article, but believe me, this works so well to raise chicks! Just feed and water them when you feed and water the others. Hens just don't go broody when we want them too, doggone it. So with a little time, a heating pad, and the coop you probably already have (since you have had chickens for 2 years) try this:
https://www.backyardchickens.com/a/yes-you-certainly-can-brood-chicks-outdoors
https://www.backyardchickens.com/a/yes-you-certainly-can-brood-chicks-outdoors