Damaged neck -Polish (3 months) attacked by hen

[schling]

One of our pullets - only 3 months old was attacked by our Golden Comet on Thurs. They were both under the coop so it was hard to see what happened but after I gave them water I started walking away, heard something andmy daughter yelled. When I turned, our Polish was flailing on her back. I quickly picked her up and tried to calm her down. Her beak was open and her eyes were closed. I thought she was dying in my arms. She may have hit her head or the Comet got her in a good place on the head.
Fri. she was able to stand but was very dizzy. Her neck is wobbly and she startles very easily (not hard to believe after what she'd been thru). We took her to a farm vet and he gave her an anti inflamatory. I can't believe she made it this long.
Today is Tues. and she is still off balance and her neck seems to go into spasms from side to side. But yesterday she started bobbing her head up and down which was different and she began eating from the ground (in the house). She also proceeded to fly over the 2 foot playpen she's in. I still don't know how her vision is because she is still easily startled.
Has anyone heard of such an extreme injury to the brain and if so, is there hope for this chicken? We were instructed to give her cortisone twice a day and it seems to help. I know this may take a while for recovery, I'm just hoping she will recover. My daughters love this little chciken.
Thanks.