You never know about chickens and broody behavior. I have a broody hen right now. She went broody and refused to leave the nest after laying only one egg! I gave her two more and hope we get at least two chicks. My other broody hen sat on six eggs, so you never know! My broody last summer with six eggs was an Easter Egger, right now my girl Maggie, a Buff Orpington, is holed up trying for a family! She has only left the nest one time too, (it's been 15 days!!), and the EE left every other day. All this to say it all depends on the hen what the amount of eggs may be and behaviors while broody! Good luck with your Orpington hen! 
