It's not going to stay in on its own. If it pops right back out and you can't get it to stay, the most humane thing to do is put her down, IMO. A week is a long time for her to be traumatized with this. My experience is with a runner who prolapsed and I brought her inside, and over the course of a few days, put it carefully back in about 40 times - every time she pooped it came back out. She was thoroughly traumatized and stopped eating. After a few days I tried a giant bandaid that room to still shoot the poop out, and that did the trick. It kept the prolapse in when she pooped and I kept her inside a few more days, monitoring, and changing the bandaid to keep her clean. Three months passed and she didn't lay, but just a couple weeks ago she laid an egg and prolapsed again. This time same scenario but band-aids didn't work. I could see that as soon as spring came it would be a constant problem anyway. Some ducks apparently are more prone to this. It was super sad for us, but we decided to put her down.