I have three hens. One of them has developed pustules that are hard and look swollen around her vent. She also has what look like eggs layed by a flea or mite, and small flea type insects around her vent and in plumage. The other two have the small bugs too, and one looks like she's also developing the eggs around her vent in the last couple days. I don't think it's red mites or fleas, but there are definitely little transparent bugs and what look to be small eggs around vents. Any idea what this is and how to treat? I'm especially worried about the pustules around her vent. Thanks!