It Is Important to Know I'm a Physicist not a Veterinarian
If You Can Convince a Vet to Treat Your Chicken, Do It
Here is my theory and therapy for what some call "limber neck" and I call crookneck.
The symptoms first show as a crook in the neck.
It usually rapidly progresses to your bird tucking her head, then tucking her head between her legs, then backing up, and tumbling over.
It usually hits young birds but can happen at any age.
It often happens when Silkie chicks are crowded, especially with more aggressive breeds (like Araucanas) in the mix.
There are other problems with similar symptoms; botulism is one.
It is unclear what causes crookneck but I have a fairly sound hypothesis. Silkie club members suggest water on the brain, vitamin E deficiency, and injury to the brain. A Silkies' brain is often outside the skull and forms the "knob" on the top of Silkie's heads. See Silkies Have a Hole in Their Head. Brain injury is the cause I feel fairly certain about.
Water on the brain was seen in a necropsy of an affected bird in Florida. Prednisone (read on about different opinions on prednisone) was suggested as symptomatic relief and vitamin E and vitamins B complex are both good for neurological disorders. Selenium helps animals absorb vitamin E.
Here's what I do for affected birds. If started before symptoms get severe, the bird will usually totally recover.
It is important to be sure your bird gets enough to eat and drink while she has this problem. Birds with severe cases of crookneck can't eat and drink enough to survive. You will need to gently place their head in the feed dish and carefully dip just the tip of the beak in water. Be careful not to dip too far into the water and to not stress the bird while trying to help.
In severe cases, you will need to use a hand feeding syringe and hand rearing formula for cage birds. My boy Spot had to be hand fed for 2 months but he survived to father lots of healthy chicks.
If you and your bird are lucky, hand feeding and the vitamins will be all that is needed.
Before I present my treatment I need to mention that a couple vets have expressed concern about using prednisone. They suggested instead giving Celebrex or Metacam. They are also anti-inflammatory. I can understand their concern but I gradually reduce the dose and do not just one day stop giving prednisone. I have seen no adverse effects and prednisone is inexpensive while Celebrex and Metacam are expensive.
Many vets think prednisone OK and in fact is was prescribed for a bird of mine.
If started before symptoms get severe, the bird will totally recover. The following is for an adult about 2 pound bird. Scale back for smaller birds. Do not over do the selenium; it is toxic in large amounts. Animals are more tolerant of vitamin E especially and of vitamin B.
Do not abruptly stop prednisone, the swelling rebounds. Decrease the dose gradually. Recovery can be slow; continue the vitamin E for several weeks at least.
You can get prednisone from a vet; just describe the problem of swelling in the brain probably due to injury. Yes Silkies' brains do stick out through a hole on the top of the skull. Print the pictures at Silkies Have a Hole in Their Head and show them to your vet.
Your vet might suggest a different anti inflammatory like Celebrex or Metacam.
You can get the vitamin E, selenium, and vitamin B complex or liquid vitamins at any pharmacy.
Diana Hedrick asked Janny Hermans, a poultry specialist in the Netherlands, to review this Therapy. Janny Hermans' reply is below. Janny Hermans warns about over doing the prednisone and agrees the vitamins E and B can also help. She does however address the possibility of poisoning causing the neurological problems. She suggests an antibiotic in case bacteria are the source of the poison.
I'll try to write English and I'm sure we'll understand each other. If you really found her on her back, that means she totally lost her balance. This is a severe neurological symptom and therefore I agree for a great deal with the article of Alan. I don't think your cat attacked her. Then you should see wounds on her head, if the symptoms are so bad.
It's more likely that she suffers from an intoxication of any kind. It's difficult how to react, because there are no real detoxification methods. Antibiotics are a good thing and I think your choice of amoxicillin was a right one. Amoxicillin passes the blood brain barrier and is our first choice antibiotic in Streptococcus or Staphylococcus infections in the brain. Amoxicillin also is the best antibiotic in an infection with Clostridium perfringens (a brother of the bacteria that causes botulism). These Clostridia bacteria all cause cramps or paralysis of muscles. The real problem is that these bacteria also produce toxins against which no therapy is possible.
So my therapy would be the same: Amoxicillin for a day or 7 and perhaps a little bit prednisone (I've never heard of the hole in Silkies brains, but prednisone causes no harm if you give it shortly). A little bit of vitamin E and B can help also.
I hope I helped you a bit!!
Janny Hermans Poultry veterinarian