Feather loss on backs, saddle. Possible giardia.

[Mouchie1961]

I have ten hens, just turned one year old. Most of them have feather loss on their back saddle area, and below the tail. No roosters. Although I have witnessed one of the leghorn hens mounting others, infrequently.
Because of this, I had a fecal run which came back as positive for giardia. Two different vets suggested not treating them, that healthy hens would get through it.
They have a nice size coop and run, and they free range an hour or two a day, when I am home.
I have tried dusting them with permethrin. Though I don't really see any external parasites.
What am I missing? Anyone else have feather loss from I think I'm going to try Safeguard and see if that helps, as that is one of the treatments for the giardia. I am still not sure what the egg withdrawal time is. So confusing, the dosing, and withdrawal.
Any thoughts would be appreciated. Thanks!

 

[Eggcessive]

Feather loss can be caused by feather picking due to fedding less than 16% protein in the diet or unbalanced diet, boredom due to not getting outside to roam, or overcrowding. Some breeds are more prone to being bullies. I wasn't aware about giardia causing feather loss and itching, but after reading some, you are right. The article I saw stated that anti-protozoal medications such as ronidazole or metronidazole (FishZole or Flagyl) are used to treat it. Safeguard (fenbendazole) is used to treat it in dogs. I would increase your protein for a bit to 20% and use a flock raiser type feed plus have crushed oysters shell available for the extra calcium. Four square feet of room for your birds would be adequate, but nothing beats getting them outside to end boredom. Here is some reading:
https://www.beautyofbirds.com/giardia.html
http://www.merckvetmanual.com/digestive-system/giardiasis/overview-of-giardiasis