can worms cause chickens to go off their legs?

So I posted a month ago about a hen I had who was off one leg. I initially thought bumble foot and kept her isolated, quiet, administer penicillin, etc. Then she got overall weaker on the other leg and stopped supporting her weight. This took about a month to happen. She is still eating and drinking well but is very thin. I took her to the vet suspecting Marek's and they are doing a blood test to see if that's the case. Initially when I isolated her I gave her pour-on ivermectin. Today I was cleaning up her poopy feathers and she blasted me with diarrhea in which I found a long white worm. I had assumed the ivermectin would have addressed that (she had it weeks ago) but maybe it is not effective against round worms? I found another worm just like it in the (normal looking) poop of a healthy chicken. So, clearly I have a worm infestation and have to worm my flock. My question is - I know ducks can go off their legs if they have a serious enough worm infestation. Can the same be true of chickens? I feel so stupid for not thinking of this sooner. Also, I have wazine I can give them. I'd prefer something without a withdrawal period if there are any other options but obviously the priority is to deal with the worms ASAP.

 

Thank you - these are all very helpful webpages. I am giving her Wazine in her water just to see if it helps. I had been giving her Rooster Booster in her water but maybe that was not enough for the potential vitamin deficiency...

I should know this week if Marek's is the culprit. It's such a shame about this poor gal though. She is a great bird, one of the ones I really like. And the only one who lays double yolkers. I am crossing my fingers that it's not Marek's but we will know soon.