Help! My hens have roundworm. Should I use Wazine or Ivermectin (topical) or something else?? I've spent the last several hours searching this forum

[Valerie6304]

but there is SO much information and conflicting information that now I'm thoroughly confused! I have 12 hens ranging in age from 8 months to 6 years old. I haven't ever treated them for worms but I found one in some poo the other day. I'm pretty sure it's a roundworm.
They are going through molt so I don't think I can give them fenbendazole. I read it affects new feather formation.
I picked up some Ivermectin 5mg pour-on for cattle. The feed store owner said 5 drops on the skin for a regular size chicken. After reading all the posts, it seems this might be too harsh for them? I don't want to do anything to hurt them or make them sick. He also said he doesn't throw away the eggs but that some people do.
Wazine is hard to find here but I might be able to get some this weekend if that would be better to start with. Please help!!
Thank you!!!!!

 

[Eggcessive]

Roundworms are the usual most seen in poop, since the eggs and the other types are too small to be seen easily without a microspcope. Wazine is no longer being manufactured as far as I know. Valbazen is a good wormer, and you can find it in a few feed stores, but online it is easy to get. Dosage is 1/2 ml for a 5 pound chicken, given once orally and again in 10 days. Southern State sells it, along with Rural King. Here is a link for it online:
https://www.jefferspet.com/products/valbazen-broad-spectrum-dewormer