There is no surefire way to tell the exact age of a guinea pig especially without a medical exam, but you can look at some factors like weight and nails to approximate.
In my experience, young guinea pigs weigh around 200 to 400 grams and then during adulthood their weights will stabilize to around 600 to 900 grams. For the nails, younger pigs usually have sharper and more pointy nails than adults, and adult nails are usually thicker.
If you would like a more thorough assessment, you can always consult a vet in your area and ask about your piggies’ age.
Yes, there are treatments for mites. Veterinarians use Ivermectin or Selamectin for mites treatment, and the dosage depends for each pig. If you suspect that one of your piggies has mites, go to the vet immediately because it can quickly escalate into hair loss and infections that can be painful for your guinea pigs.
Your piggy’s situation does sound alarming; the things you did so far are good and will help ensure that she still gets the nutrition she needs. I’d say that you continue hydrating and force feeding her if she still doesn’t eat by herself, you have to do this every few hours or so. You should also monitor her weight to see if the amount of feeding is enough to retain nutrients and weight in her body; a drastic drop in weight in a few hours is not a good sign.
If you have probiotics in stock, this will also help to increase her appetite while she still has no access to a vet that will treat her.
Many vet offices that treat guinea pigs are open during weekends. Some of them are Vets In Practice Mandaluyong, Animal House Makati, and Animal Care Specialists in Tiendesitas. For more options, check out this page.
I hope your piggy gets well soon!
It’s okay to feel that there is little or no progress! Sometimes after the first few milestones it can take a while for the next big progress to happen 🙂 But as I see it, I think you’re doing great. The fact that your pigs are comfortable with hand feeding is already a great sign!
Some piggies like to interact with their humans during floortime but a lot don’t, since they take floortime as a time for themselves to play together in a big space. Don’t feel so bad if they’re not interacting with you during this time since they’re just busy with exploring their surroundings. Just stay there to supervise them and they will realize that you don’t mean to harm them 🙂
It’s perfectly normal for piggies to be nervous when they’re in a new environment so you have nothing to worry about. Since they have already been with you for one week, you can already try handling them. But you should do this slowly and if they are still freaking out when you are trying to pick them up, you can try picking them up with a towel, tunnel, or cuddle cup. Eventually, they will get used to you handling them and they will realize that laptime and floortime aren’t so bad after all!
I used to give my piggies Oxbow pellets but since there’s a shortage of Oxbow supplies right now, I give Jolly pellets as a substitute but I give it to them sparingly because it’s alfalfa-based.