I don't remember who thought they had mites and I said they were too big to be mites. I found one today on a discarded feather.
See that speck on my thumbnail?
View attachment 2868492
Circled:
View attachment 2868498
Mites come in different sizes. They also have prefered habitats.
That looks like it could well be a mite. Now you need to work out which sort.
Northern Fowl mite are large enough to see reasonnably easily with the naked eye and they live on the chicken.
You can't afford to mess about with Northern Fowl mite. If a chicken is going to get seriously sick from a mite infestation the chances are Northern Fowl mite will be the culprit.
Red mite are the most common, at least in the regions I've lived in. They do not live on the chicken. They live in the coop. They are, if your coop doesn't have too many nooks and crannies (coop builders take note. Simple flat surfaces for build and removable everything for ease of cleaning) fairlly easy to eradicate. I use a blow torch but the are chemicals such as Permethrin that work well. Even washing down the inside of a coop with warm water and a mild detergent will rid a coop of red mite.
What you may have in the picture is feather mite. These are relatives of the Red Mite but they live on the feathher shafts of the chicken. Easy check is to lift the feathers and look at the base of the feather quill. If the base of the quill is rough and looks like stuff has built up around it then you've got, or rather your chicken has, feather mite.
Permethrin works well and I am told Ivermectin does as well.
Scaly Leg Mite are tiny and I cant see them without a magnifying glass. They live under the scales on a chickens leg.
All the above mite treatments work for SLM but just as effective is to slather the leg in Vaseline. This suffocates the mites. BUT, the scales do not return to normal once the mite is dead. The chicken has to shed the old scales and regrow new befor it looks as if the problem is taken care of.
For all treaments, beit lice or mites you need to treat more than once. Mites and lice lay eggs and the chemicals do not kill the eggs. The blow torch does but obviously this can't be used on the chicken.
The eggs hatch and the infestaion rolls on.
I treat for SLM 3 days in a row, wait two weeks and go again.
NOTE. There is no known natural remedy that will rid a chicken of a seriouus mite or lice infestation.