As HesterF says Orpingtons need to be lifted every day as they are known to sit tight and cripple themselves.
One going broody shouldn't affect the others, but you may get more simply because of the time of year. I'm not sure from your post if you want a broody for hatching, or if you are just giving her eggs to keep her happy. She can be 'broken' out of her broodiness, which avoids losing too many eggs and avoids risking the health of the broody. If you want to hatch she needs to be in perfect health, free of lice and mites and over two years old. Younger and there is a risk she won't go the course and she may, as ours did, panic and eat the chicks as they hatch.