Hi
I'm so sorry to hear of the problems you have been having. Fox attacks are very upsetting and once it happens they will continue coming until you pen your girls up. I used to love to free range my flock, but I have eventually had t pen them in order to keep them alive. The fox was even coming when I was there during the day and snatching one.
As regards your girl with the prolapse, it is difficult to make out but does she have a separate wound below her vent that the tongue like tissue is coming out of or is it all just hanging out of her vent. If the latter, it would appear that you are dealing with a rupture as well as a prolapse. The combination of a prolapse and ascites and the yellow colour of her skin would suggest that she may be suffering from Fatty Liver Haemorrhagic Syndrome and perhaps the stress of the fox attack has caused a major haemorrhage and resulted in the ascites or the strain of pushing an egg out and the prolapse has caused the rupture. You really need to keep that tissue as clean as possible (not easy I know in that location) and moist to prevent it from becoming necrotic. Raw Honey or Prep H are often used or triple antibiotic ointment. If it is coming out of a hole below her vent it suggests that her abdominal cavity has been breached and that may well be her lower intestine herniated out. I think you are unlikely to be able to put it back in and keep it there without surgery and the concern would be that infection would set in even if you do manage to get it to stay in because it will be contaminated with faeces. Veterinary assistance would be advised. 
If it is all just hanging out of her vent, then it is one of the most substantial prolapses I have ever seen. The only hope is to gently keep trying to push it back in and hold it there. Use copious amounts of Preparation H to try to reduce the swelling and keep it moist. It may take days or even weeks to resolve but it is very severe and my thoughts are that she will probably not survive.
Veterinary assistance would be appropriate if your finances run to that (personally mine don't) and if she starts to look dull and go off her food, it might be kinder to euthanize her but do keep trying as long as she is looking bright and eating.
Out of interest, what do you feed your flock? I'm wondering if they get corn or scratch as these can cause Fatty Liver Haemorrhagic Syndrome particularly if you are treating them every day and are perhaps being too generous with them. Reassessing your flocks diet is always a good idea when you get an ailment like this. It may be unrelated and I may be wrong about it being Fatty Liver but always a good idea to look at the treats you give your flock and decide whether they are healthy and if you need to cut back on them.
I wish you lots of luck with her. Please keep us posted with her progress. Will be keeping my fingers crossed 

 that I am wrong and she pulls through.