She looks like she has a prolapse. This is not too unusual for new layers, but isn't extremely common, either. Some usual causes are insufficient calcium (creating weaker abdominal muscles) and laying very large eggs, or a pullet that's just beginning to lay and isn't used to it.
Heres what to do: Isolate her immediately from the other birds. They will pick at the prolapse, and she might harm herself when running away from them, or jumping onto high rooster, etc. A dog crate would work well.
Start soaking her lower half, twice a day, in a warm water bath. Make this water 95 degrees, and soak her for twenty minutes each time. This will help relax her muscles so that she can draw the prolapse back into her body. It will also keep the prolapse moist and relatively clean.
After each soaking, and throughout the day, apply some honey and some Witch Hazel, or Preparation H. I recommend the honey and Witch Hazel, as it helped one of my birds when she had a prolapse. All three items help reduce swelling, and the honey keeps it moist and lubricated.
Once a day at least, I'd recommend trying to gently push the prolapse in. It probably won't stay in very long at a time, but should eventually help.
Stop her from laying. To do this, keep her in the dark. Witholding feed for most of the day will also help. Witholding feed also has the advantage of preventing a lot of feed from going through her system, which can irritate the prolapse, make it dirty, and prolong the healing period. Give her some feed each day at night, though, and always provide water.
Adding calcium to the water is a good idea as well. This will strenghten the muscles, and help her pass any eggs if she is still laying.
Hope this helps!
