Pictured here is my 2(?) year old Marans, with some kind of hard mass on her underside. She is lying on her side, her vent is on the left side. Vent is fine. She's had a messy butt, so I brought her in to take a look and this is what I found. I bathed her in Epsom salt bath and put antibiotic ointment and VetRX on the mass. Anyone know what this might be?