fuzziebutt ... you got it.The link that I gave you tells how they got it. Somehow, there is a cycle of roaches with the worm larvae, the chickens eating the larvae, and it hatching in the chickens, and making it's way up the sinus'. Or, it gets pooped out, the roaches eat it, and the chickens eat the roaches again. Use the Vet Rx like the link says, and do WHATEVER is necessary to exterminate the roaches, even if it's the hotels in the coop. And I would remove these chickens from the healthy ones until they are well.
And I don't think it is supposed to go down her throat. You hold the chicken upside down, and use a qtip to swab the solution on the roof of her mouth, and swab it alot. If I understand it right, it should come out of the top of her mouth, and run out of her eyes also. That should wash the worms out, and kill what worms are in there. And continue to do it until no more worms come out. Is that what it sounds like to you?? This is foreign to me, but let's see what others say about it. I think that is what the directions are saying.