This is just a thought as I came across your thread, but it sounds like Botulism to me, (I am by NO means an expert, just a random thought)... It may very well NOT be this but I looked it up and here is some info on it...
First symptoms; Nervous signs, weakness, progressive flaccid paralysis of legs, wings then neck, then sudden death.
Treatment
Remove source of toxin, supportive treatment if justifiable, antibiotics, selenium.
Have you any antibiotics on hand? It may help save some until you can hear back from the vet...?
And I found this on another site;
Botulism is caused usually by a chicken eating something rotten or moldy- moldy feed behind a bin or a dead mouse etc. Affected birds start out weak (weak in legs) and progress to paralyzed within 24 hours. Usually the bird has a weak neck and will often drool if they can no longer swallow. Appetite is reduced, at least after a few hours of "infection" and the bird doesn't want to eat at all after about 12 hours. Sometimes they will be thirsty, but that depends on the individual bird. Birds with botulism can be treated- keep them in a cool place (opposite to how you would usually treat a sick bird) as the toxins metabolize a little slower this way and the body may be able to deal with them. Birds that have botulism typically die within 24 hours- if you can get an infected bird past 36 hours, your chances increase significantly of having them survive. Here's how to treat them:
Flushing toxins using activated charcoal:
Go to your pet supply store and pick up activated charcoal (for fish tanks). Crush up into a very fine powder, about 3 tablespoons. Mix this with half a cup or so of water- enough that the charcoal is mostly suspended but not so much that you've diluted it too much. Now, while you're at the pet supply store, pick up some airline hosing too (again, for fish tanks). You'll also need a catheter tip syringe, 35 cc. Measure the distance from the duck or chicken's bill to the crop (in a duck's case, the length of the neck or about 10-12 inches). Cut the hose to this length and make sure the end isn't sharp. Fit the other end onto the syringe (you may have to heat the end of the tube to fit it onto the catheter tip syringe). Suck up a full syringe full of the charcoal mixture, making sure that you suck all the liquid out of the tube before you stick it down their throat. Open the bird's mouth- at the back of the tongue, there's an opening, called the glottis. This is the opening to their windpipe and NOTHING should ever go down this opening. As long as you avoid this hole, you'll be fine. Wet the tube, then slide the tube down the throat (someone is holding the bird now). If you hit resistance, stop- if you are far enough down the throat, administer the fluids slowly. If not and you still have a lot of the tube sticking out, then pull back and gently slide it down again. Sometimes it's just the position of the neck that causes problems. Administer the 35 cc or however much the bird can take. Do it slowly enough that you can monitor if any fluids are coming back up the throat. If this happens, pull the tube out (pinching the tube so no further fluid comes out) and drain the birds throat and mouth, then lift the head up to allow the bird to breathe. This doesn't happen very often, especially if you are careful. To increase effectiveness of the charcoal, repeat this procedure every 6 hours for 24 hours.
