You now have 23 chickens. They need about 4 sq ft each in the coop. 23x4 = 69 sq. Ft. That's how big your coop needs to be to accommodate this many chickens. So basically at least 7x10 ft. Standard measurements are 8x10. Is your coop this big? Each chicken needs about a foot of roost space and the roosts need to be about a foot away from the wall. Do you have 23 feet of roost? If you're using ladder style roosts, are they sloped enough so nobody gets pooped on from above? Are they far enough apart so that chickens higher up can't peck lower chickens?
If these problems are not resolved, your chickens are sleeping outside because they do not have room inside, are not comfortable inside, or do not feel safe inside. Resolve these issues and then take your "campers" inside after dark. They will stay, partly because they can't see to do otherwise. And when they feel safe and comfortable, they will roost inside of their own accord.