Chicken has Bald Patch on her Bottom

[NapoeleonDynamite]

Hello,
This morning, I noticed that one of my hens has a bald patch on her bum (pictures below). I did a bit of research and there seems to be a variety of things that could be going on, so I'm not sure what's wrong with her. I picked her up and looked at the patch, and her skin seems to be healthy and shows no signs of pecking or parasites.
Does anyone have any thoughts as to what is wrong with her? Could it be egg-laying or molting?
Thanks!

 

[HeatherKellyB]

Hi there! I'm sorry your girl has a balding bottom. Have you checked her and the coop over really well for lice and mites? Checking at night is the best time to do this.
It's possible that she's being plucked by her flockmates.
How many birds do you have and what size coop do they sleep in?

 

[HeatherKellyB]

@aart has the best links/info for checking for lice and mites and is all around very knowledgeable

 

[NapoeleonDynamite]

Hi there! I'm sorry your girl has a balding bottom. Have you checked her and the coop over really well for lice and mites? Checking at night is the best time to do this.
It's possible that she's being plucked by her flockmates.
How many birds do you have and what size coop do they sleep in?

Hi! No, I haven't checked the coop for mites, I'll do that! There are 4 chickens in total, and their coop is probably 6x4?

 

[NapoeleonDynamite]

Hi! No, I haven't checked the coop for mites, I'll do that! There are 4 chickens in total, and their coop is probably 6x4?

So I just did a quick sweep of the coop and there do appear to be a few tiny bugs in the wood cracks... I'll look around, but what should I do?

 

[HeatherKellyB]

Are you in the US?

 

[HeatherKellyB]

You'll need a pymethrine spray or dusting powder or Elector PSP. Either are effective treatments for mites and lice. If you're not in the US, there are different options

 

[HeatherKellyB]

If you have a TSC nearby, they carry Gordon's. It's an affordable pymethrine liquid. The mixing directions are on the attached booklet. You'll need to clean out the coop completely and then spray every crack and crevice. Mites hide out in the coop all day and come out to feed at night. They are tiny so they can fit between roosts and walls, any tiny crevice. Be sure that you take everything you remove from the coop far away and burn it. You'll need to treat each bird too.

 

[NapoeleonDynamite]

Are you in the US?

Yes

 

[NapoeleonDynamite]

If you have a TSC nearby, they carry Gordon's. It's an affordable pymethrine liquid. The mixing directions are on the attached booklet. You'll need to clean out the coop completely and then spray every crack and crevice. Mites hide out in the coop all day and come out to feed at night. They are tiny so they can fit between roosts and walls, any tiny crevice. Be sure that you take everything you remove from the coop far away and burn it. You'll need to treat each bird too.

Alright. I've looked at some organic mite-killing sprays on Amazon (is that an okay route to go?), but I will do a thorough cleaning and spray the coop with something. Thank you so much for the help!