A pic can help, but mite eggs do indeed look like little white or grey bumps on the feather shaft.
I use ProZap poultry dust; it contains pyrethrins. an insecticide synthesized from plant extracts (simply put, anyway). You should be able to find this at the co-op or farm store, or order online from Jeffers or similar place.
Since mite eggs are impervious to the dust, you can only kill the adults. The eggs need 4 days to hatch, so you will want to dust once, then dust again in 4-5 days to kill the next generation.
I dust at bedtime. Just put on some rubber gloves, and work a small handful of dust in the vent area (pretty sure to have the eggs if you found them elsewhere), then a bit under each wing (where they will run from the dust). If there is a bit on his neck get that too, but don't get in his eyes. Pop him back in the coop, and you're all done.
Mixing a bit of diatomaceous earth into the coop shavings will help keep mites down. You can do a search on this forum for more info on that . . . lots of conversations held on that topic!
Hope that helps. Good luck!