One of my ~6 month old pullets (hatchery stock Silver Laced Wyandotte) seems to have a problem missing her fluffy butt feathers when she defecates. She does have a particularly fluffy butt, however the others do as well, and I haven't seen this issue. Is this a sign of something? Her stools look normal, there's just getting to be a build up back there. We've cleaned her up a couple times, but it just keeps occurring. Any ideas on causes and/or solutions?