I would just put them out without heat. Your temperatures are good, the smallest chick still has a decent amount of feathers, plus the others will probably huddle with her at night to keep her warm.
You can put out the heat plate if you wish, but it wouldn't surprise me if she doesn't choose to use it at all.
You can put out the heat plate if you wish, but it wouldn't surprise me if she doesn't choose to use it at all.