Do you have hawks in your area? 2 months is still small if you have any predators that are going to get in your yard to get them. When mine were 2 months, I built an enclosed area within my yard, with a poultry netting top, which kept them a bit safer, plus allowed them to get to know the older chickens. Then when they were another month older, I opened the pen and let them explore, using that enclosed area for shelter.
They might not automatically go home at night, but they will recognize the coop as a familiar shelter. You might need to direct them home each night. If you train them to go around dusk, you'll be creating a good natural habit for them, and eventually they'll go on their own. If you need to get them in the coop before then, you'll want to use a treat.
