I was cleaning out the nest when I saw something running around on the youngest bird's neck. I picked him up taking a closer look when I found out he was infested with mites, and not just him, all 4 babies. I have no idea on how to deal with this infestation or how they even got them in the first place.

¿What should I do? I would really appreciate some help.

Are the babies outside? well, mites just live outside, and get whoever they can. Its summertime, its hot. Also there are ticks, mosquitoes, flies (they like to lay eggs on something warm and then ugly maggots hatch and eat your pet alive, happened once to my rabbit)
I have no idea what to do with mites in baby birds but a vet should know. Please take your chicks to the vet as soon as possible. I would also bring them inside ASAP

It's best to talk to a vet. This article might be helpful too: http://www.justcockatiels.net/red-mite-attacks.html The part about immune system herbs is dubious, but the stuff about actually getting rid of the insects is probably accurate.

another link
https://www.petcha.com/bird-mites/

Thanks, but that link is mostly about scaly face mites, which is probably not the same thing that's attacking the babies. Scaly face mites mainly seem to go after budgies, and the way they attack the bird is very different.

I use mites against mites... if that makes sense?

I can buy mites from the Laelapidae family online . They hunt down the blood sucking variant and eat them. I'm not sure if you could order some where you are... And I'm not sure what kind of mites the ones I get are, they are branded: Dutchy's. But I believe it's not the real name and only a brand.

If you want to try google translate on the web-page I buy them from, be my guest: http://www.refona.nl/refona/pages/nl/dutchy-s-r.php

Going off topic: Bob, I see that Photobucket has swallowed your signature. They have become too obnoxious to use, and many people are switching to Imgur which is a lot more user friendly.

great article. How do people get Sevin? maybe my birds have mites, too.

You can get Sevin at Home Depot or just about any other hardware store. You might be able to get it at large stores like Walmart too. It's unusual for indoor birds to get mites, but yours spend some time outdoors so it's not impossible. Sevin is an insecticide, so don't treat your birds with it unless you're sure that there's really a problem.