Well, actually she waddled like a duck for about a week. During that time I took her to see the vet, who gave her a good examination. There was an egg in her cloaca which she left there as didn't want to hurt the chicken trying to get it out. It actually arrived by itself the next day, a soft-shelled egg. She gave Greta a calcium injection and a painkiller. I kept her on her own for the week. I gave her vitamin-enriched water, extra protein with her food in the form of grated cheese and mealworms. At the end of the week she was upright, a bit wobbly but upright and raring to get back with her chicken pals (four of them) so I put her back in. She's been fine ever since. She and the other girls now get a dish of natural yoghurt every day as a treat in the late afternoon, they get a few extra protein treats in the morning. Everything seems to be fine again. Somebody messaged me to say it sounded like Marek's disease and I tend to agree, although she was actually a year old when she got struck down. The vet never mentioned that and didn't really know what it was. One of the other birds started with a similar thing (Buff Orpington one and a half years old) but not as bad. She was okay after a week. Again, maintained the same things: increased the protein and gave natural yoghurt as an afternoon treat. She's absolutely fine now too. My birds are wormed regularly, i use Dermaceous Earth to help with parasites internal and external, they are not overfed and anything they do get is healthy for them.