My 20 week old pullet started laying Thanksgiving Day. Since that time she has had a dirty looking rear off and on. I've checked her vent area and it's not blocked or weird looking. But her rear feathers keep getting dirty/messy. Is it because she is the only layer pullet and the rooster is riding her too much? What do you think is causing this? Is this normal for white leghorns? What could be happening here? I changed her feed to Layer feed over the weekend and she's been getting more treats lately (yogurt with egg shells & oyster shells) - could this be causing the issues? She's not laying regularly yet. Yesterday was the 1st time in 3 days that she laid and egg - it was "normal" but smaller and had lumps on the outside - calcium deposits? Today I found two softshelled eggs in the manure box. https://www.backyardchickens.com/forum/viewtopic.php?id=605049 page #9 shows the eggs from today Here's her back end.