Valbazen is best for worms, but you may have an easier time finding it online. SafeGuard Liquid Goat Wormer is easier to find locally. dosage of either one is 1/2 ml orally, then repeat in 10 days. Was your hen vaccinated for Mareks disease? She has been ill so longs now, with lameness and green diarrhea, so I would read some about that disease. It can cause problems with normal immunity to common diseases brought on by a low white blood cells count. Mareks may not have anything to do with her illness, but I thought I would mention it just in case the lameness is related. A picture of her lying down may help. Here are a few links about it:
http://extension.unh.edu/resources/files/Resource000791_Rep813.pdf
http://partnersah.vet.cornell.edu/avian-atlas/#/disease/Marek's_Disease
https://www.backyardchickens.com/a/the-great-big-giant-mareks-disease-faq
http://extension.unh.edu/resources/files/Resource000791_Rep813.pdf
http://partnersah.vet.cornell.edu/avian-atlas/#/disease/Marek's_Disease
https://www.backyardchickens.com/a/the-great-big-giant-mareks-disease-faq