Is this mites or molting or over breeding?

[Rooka_2]

So, I'm not quite sure what's going on here. I have been noticing all the silverlaced orpingtons are missing butt feathers to the extreme.
Here are my facts:
-They hatched August 29th.
-5 Roos
-4 Hens.
-All 4 hens have bare butts, as well as two Roos.
-In this coop with them are 6 isabel orpingtons hens, 1 black mottled Houdan rooster, 4 silkie Roos, 4 ducks, 5 olive egger hens and 3 geese.
- only the silverlaced orpingtons look like this, none of the other birds are missing feathers.
-They have been in the coop with everyone since October. New coop for everyone, there was no established territory.
- I believe I'm having a slight issue with mites this winter. They are in a heated barn room, when I pick up my birds I get these black bugs that are smaller than a pin head on me and they can be really itchy. The birds I've encountered it on (two of my silkie hens who are in a different coop) I've treated with ivermectin. I'm tempted to treat everyone. I did very recently just add dust baths to both coops (stupid me) and they have been using them a lot. I added a ton of DE in hopes that it would help with their bug problem.
- I'd also mention that my silverlaced orpington Roos don't seem to be "active" yet. They're not crowing, they're not all over the ladies, they're super friendly still, every single one of them. I've been waiting for them to start pumping hormones and get mean.
-They're not fully feathered out yet so I've been holding off on getting rid of the extra Roos till I can confidently pick which one is nicest in looks and personality.
Here is ones behind, I belive this was roo that we grabbed.

I have quite a few silkies molting right now so I'm really hoping that's what it is and not those depluming mites.

 

[BobStuart]

Is she laying?

 

[Rooka_2]

Is she laying?

So this is a Roo, and no none of the silverlaced hens are laying yet, they're only 5 months old- so maybe soonish?

 

[Eggcessive]

That is feather picking which can lead to vent damage and cannibalism, even death. They may be overcrowded. Four month old cockerels can start running around creating havoc with the pullets or hens. They will start mating hens and challenging the others at any time. I would start weeding out the extra cockerels and find homes, or separate in a different pen.

How much room are they in? Are they getting out to free range? What type of feed and the % of protein in the food? Ducks and geese should not be in the same coop, or they may pick on the pullets. Is there too much light in the coop?

In dealing with mites, they hatch every 5 days, and then the newly hatched ones will lay more egsgs. Treatment needs to be repeated every 7 days until gone. The facilities need to be treated with permethrin every 30 days. The bedding should be removed, and once the coop/roost, nests have been treated treated, fresh new bedding should be added. The mites can live in the cracks of the coop, so may be hard to get rid of.

 

[Kiki]

How many birds do you have, what size is your coop and what exactly do you feed your flock?