open crop

One of our new hens, Rosie, has been to the vet this afternoon 'cos she wasn't eating and looking very uncomfortable. He sliced open her crop, pulled out a heap of undigested grass and spinach leaves, stapled her skin together and we returned home.
When I checked her an hour ago, she's managed to tear and peck herself into a blooming mess. I've sewn her crop together, bandaged her up and I'm hoping that tomorrow she'll  be ok. She is in a seperate pen from the other hens, and hubby suggested a plastic collar but has anyone any idea of how I can prevent her damaging herself further?

One of my hens had to have a blockage removed surgically by the vet and she was stitched up properly and healed well.  Seems your vet did a bit of a rough job