Stop feed the oatmeal and yogurt! These things are bad for chickens.I have the same problem with one of my white plymouth rock chickens, she is on purina layena pellets, she gets oatmeal mixed with plain yogart every morning.......i have never seen another chicken pluck at the vent area..i do wash the vent area frequently, just started using baby shampoo........her poop is a bit watery, but has some solids...been giving them vitamin water and electrolytes...is there something i can wash her up with???