Also, how old is she? She looks like she has been over mated.... do you have one or more cockerels? She also looks twisted in that photo. Does she have wry tail? Is she able to walk? She looks like she has her wings out to balance herself or is that the photo angle?
The white poop is usually urates which are the bird equivalent of urine. If nothing else is being passed then it can indicate that her gut is obstructed. Being egg bound can do that, but there are other possible causes. Having answers to the above questions and more photos or better still a video (needs to be downloaded to You Tube or similar and a link to it posted here) will help to narrow down the possible diagnoses.