Possible Mites

[Qpigs]

So my girls have been with us for a week and I'm concerned we may have mites. They seem to be itching a lot, and I've spotted some bald spots on Muffin behind her ear and her back leg, and a small patch on Skittles. They are well in every other way, munching veg and playing. Can this wait for the vets to open on Tuesday (it has to be a bank holiday)? Anything I need do for them in the meantime?

My calming husband is away for the weekend so I'm feeling quite anxious and I'm still so new to piggies.

 

[Piggies&buns]

All piggies have symmetrical bald patches behind each ear. What I can see on the first picture does not necessarily look like the normal bald patch behind the ear though.
What you are seeing on the tummy are nipples.

It would be a good idea to have a vet check them.
The guide below details parasites

New Guinea Pig Problems: Sexing & Pregnancy; URI, Ringworm & Parasites; Vet Checks & Customer Rights
Guinea pig body quirks - What is normal and what not?

 

[Qpigs]

The photo isn't great, there is definitely dry patches on her legs. As long as they are eating and drinking, can it wait until Tuesday? I've read too many horror stories already.

 

[Piggies&buns]

They may have bald patches on their front legs and that be perfectly normal.

 

[Free Ranger]

Don't panic - mites aren't something that appear overnight and some pigs carry them for long time until they're spotted so at this point, if they've got them, they'll have had them for a while anyway. It can wait until Tuesday unless they're so heavily infested they start to have seizures and that looks pretty unlikely from the pics and what sounds like happy normal behaviour. The treatment you will get might be an ivermectin spot-on lotion (called xeno-450, or mini-50 for baby pigs) which kills both lice and mites. It's weight-dependant so it's important to get a vet prescription so the vet can calculate the correct dose. If you get this you will be treating both pigs at the same time with repeat treatments after 2 weeks and then after another 2 weeks. Sometimes when they are first treated there is a bit of an itching frenzy for a couple of hours while all of the mites die off but this does calm down and everyone is happier. If you don't see this they might not have actually had very many!

Piggies have 2 nipples (usually!) down on the tum near the back legs and 2 bald spots behind the ears. Second pic definitely nipple. Can't tell which bit of pig the first one is. Sometimes in an older pig you might see nibbling and balding on the back legs which can indicate a bit of arthritis - yours are a bit too young I think! And occasionally you can just get a random bald bit with no obvious cause.