My hen that has two vents is now 6 months old and just started laying eggs.
Both of her vents are work, so we have to trim her tail feathers to keep them clean. Every once in a while I soak her bum to help keep it clean. SHe does not seem to be uncomfortable in any way. However, when she lays her eggs, she is unaware when she is doing it. So, her eggs come out wherever she is hanging out. We find them everywhere in the coup and they are usually covered in poop as well. I call her my special needs chicken, and we love her even more since I spend the most time with her. Her name is Penny… and my husband calls her Penny double lane.
I hope this helps you in some way and you are able to make the best choice for your hen.