I dip with mineral oil (each leg) every day, for at least 2 weeks to smother the mites. Veg oil will work. Some use vaseline. If you have a whole flock to do you can put a pan in front of their door full of oil I have read.
Some also take a brush to the legs gently after soaking awhile...haven't tried that.
It looks like it is a mild case of Scaly Leg Mites. I'd start treatment soon, though. Try dipping the eggs in mineral or vegetable oil every day for a week or so. You can also smother the mites with petroleum jelly, or use a product like Scaly Leg Protector (like Poultry Protector, if you've heard of it).