My local guru thought it was mites because of the locale of the lack of feathers. We dusted Betty/Bobby with mite treatment (I forget what it's called) and have diatomaceous earth in the run and coop. I was planning on bringing her/him in to see chicken guru tomorrow (hopefully) to see if she recommends more/further treatment.
Just a follow up on this issue in case you didn't make it to your chicken guru (whom I am sure will say the same thing) as it is important you do follow up if it is lice or mites since you will need to do more treatment. How much depends on the type of infestation, how heavy of infestation, and how much you've integrated this new bird into your regular flock.
Look closely at your possibly infected bird.
Lice will look like flat,yellow crawly things and can be seen in daylight, usually at the base of the vent and through the feather shafts, with white nits at the base of shafts, which are the lice eggs. The good news is that lice live on the bird, but the bad news is the poultry dust only rids the adult lice. You will need to dust the infected bird again in 7 days, then again in 7 more as the new lice hatch out. You may need to dust a third time to make sure you got them all with heavy infestations. You should dust your other birds as lice are very infectious. Remove all loose feathers in the coop, and keep litter clean as lice live on the feathers that have dropped (for a short time). If this is the only bird showing any signs, and not overly heavy, you may be able to simply place poultry dust on top of the area where your birds naturally dust, and they will dust themselves...but watch for any signs in the others and be prepared to have to treat individually.
Mites are tiny red or black crawly things that can be hard to see...It is often easier to look for the blood trails which is the black markings on the skin at feather base, around the vent, or scabs left from the irritation of blood feeding. Mites can make the feathers look like they are rotting. Unfortunately mites live off the bird in the coop environment, feeding on the bird at night. To see them, you should check your birds at night with a flashlight, looking at your coop crevices and roosts and under roosts as well as a bird. You need to treat the bird in the same pattern as lice, treat in 7 day increments at least twice after initial treatment paying close attention to vent area and under wings and back of neck. You also will need to deep clean and treat your coop as mites live in the nooks and crannies and crevices of the coop itself and can be VERY hard to get rid of if you get behind a heavy infestation.
For either mites or lice, you can treat the bird with Poultry Dust (Permethrin/Pymethrin/Pyrethrum dust) or Sevin (carbaryl powder). For those heavily infested, it can be easier to put the bird in a plastic bag with its head out and shake (but don't bake) as you work the powder cloud around. For moderate infestation, I like to use an old nylon as a powder puff and puff under wings and vent. For mild infestations and prevention, I place the dust in the dusting area of the birds and they dust themselves.
For the coop, I have used Orange Guard (which contains natural orange oil) with good success at keeping creepy crawlies at bay, spraying roosts and crevices liberally; but for a severe infestations, especially mites, you would need to use the real stuff in spray form.
Diatomaceous Earth has some evidence of being beneficial to external parasites, however, it is also very irritating to the respiratory system for both bird and man, and for that reason I do not recommend its regular use in the environment but prefer to use the dusts above.
If this is the one and only bird that shows signs, and you have not integrated it into your flock...no harm no foul (pun intended)...treat in the pattern above and wait until NO signs of any infestation are left before introducing to your flock. This is the reason to ALWAYS isolate and separate new birds for at least 2 weeks, best a month, to ensure bio safety for your established flock.
Good Luck.
LofMc
