Selenium can be dangerous if too much is given. Most people recommend giving it in vitamin E with selenium capsules. The dosages I have found on other links for wry neck are 25 micrograms daily. I have also read that eggs contain selenium, as well as the dirt outside. I would keep giving the...
Many animals pant when they are hot, but also because of blowing off excess carbon dioxide in the body. If it is botulism, there could be all sorts of biological processes going on that is above my expertise. I don't want to talk you into tube feeding, but the aquarium tubing from a pet store...
If it is botulism, she still could possibly recover. The link I read said if they live 48 hours they are likely to recover, but that doesn't mean she will recover soon. It may take some time. If you have any time to spare with all that is happening, watching the tube feeding videos may help...
Be sure and keep the sick one in the shade, and make her take water. The disease takes hours to days to affect them. Then if they live for 48 hours they should recover. I can't find anything about only one-sided paralysis. One way to positively ID this is if the 3rd eyelid or nictitating...
I would remove them. If your sick one won't eat or drink, I would consider tube feeding her. A 60 cc syringe with a piece of aquarium tubing can be a tube feeding apparatus--here is a link about it: https://www.backyardchickens.com/t/805728/go-team-tube-feeding
I have been off the computer much of the day, but I am still convinced this is botulism, especially with there being a hedgehog carcass nearby. I agree with Nambroth in that the molasses and epsom salt flushes are too late. Supportive care is what is most necessary--helping her eat and drink...
Welcome to BYC. Sorry for your loss. I would wonder if your bird may have botulism or Mareks disease. Since the two died and one is now sick, I would try to rule out botulism first. It is caused by eating vegetation or animal/fish remains, and causes paralysis which starts in the feet and...