Pierce has been lounging in the corner of her cage instead if her hidey. Sometimes I hear her doing laps in the middle of the night. I am assuming she is perfectly fine but she used to hide in her hidey. Also, will the babies be tame? I feel like I am halfway there with Pierce because she usually doesn't mind when I put my hand in her cage now. She also lets me pet her now. I just know I shouldn't try picking her up while she is pregnant. Will the babies take cues like that from the mother? Also, should I take Pierce to the vet if she is pregnant 'just cuz', or only if I see any issues?
One more thing, I don't have a C&C cage yet and instead have two Midwest cages (one each for Pierce and Chester). Does anybody have any ideas on how to babyproof a Midwest cage? If the pups are all females, can I neuter Chester and let them live together again?
So yes, you can neuter the male and he will live quite happily with all the females. You cannot, however, have more than one male in with females, even if they are neutered, because they will constantly fight over the females. (They don't lose their sex drive or their ability to "do it." They just lose the ability to make babies.) So if you have any male babies, you could try to re-home them when they are old enough (do NOT offer them "free to good home," though), or you could set up two cages: one for the girls and the other for the boys (in which case nobody needs to be neutered as long as you never let them mingle with the girls).
Regardless of what you end up doing, you should get a C&C cage. A Midwest cage is barely big enough for one female, let alone any more than that. Males need way more space than females do. Two males need a minimum of a 2 x 5 grid C&C cage, but bigger is better. We have a 2 x 8 grid C&C cage for our herd of five females and one neutered male. Our pigs are 3 (babies) and 3.5 (parents) years old at the writing of this post.
You can safely pick up/handle a pregnant pig until she is really big, just be careful. Once the babies are born, you can pick up and hold them from day one also, just be careful. Babies like to leap a lot more than the adults, so be extra careful to not let them leap out of your hands or from a chair to the floor for example.
We picked up and handled all our babies from within an hour or so of birth and except for the one that died (was a runt and we did not realize it wasn't getting to nurse like the others until it was too late to save it), they are fine. Not sure what you mean by "tame" because that depends on personality as well as what they are used to. Some of piggies like to be picked up and held more than others, and that's just due to personality. Squeaky, Sugar, and Mouse, for example, like to be held, but only for a few minutes, then they are "done." On the other hand Snuggles and Twilight are content to snuggle into the crook of our necks and watch TV with us for over an hour or so. Panda doesn't snuggle into the crook of our neck, but she will lounge lazily on our lap and watch TV for just as long.
None of our piggies like to be caught, however. They are prey animals, and their instinct is to run and hide even if they trust you. None of our pigs want to be caught, but all of them are fine with being held and petted after they've been caught.
I made the mistake of getting a store-bought cage to begin with too, and it just wasn't big enough. We do keep it on hand as a "recovery" or "quarantine" cage, however. When one of our piggies is sick or recovering from surgery or something of that sort, they can stay in the storebought cage and rest without being pestered by the others and without spreading their illness to the others. So it's not like you have to throw out your cage.
I'll be willing to bet that even though one of your pigs is pregnant that neither of them are full grown. (Stores usually sell baby and barely adolescent pigs, not full grown ones.) Ours were not. They are now, and even a 2 x 8 grid cage is just barely big enough for a herd of six adult pigs.
What's more, boars grow larger than sows. If you neuter the male before he is full grown, he won't grow as large as an intact male. Our neutered male is now the same size as the females, but his intact sons (we have kept in touch with them) are way bigger than he is.
Since your pregnant pig is probably not full grown, you need to be feeding her extra calcium and extra Vitamin C. One of our moms broke both of her femurs either before or during delivery because the developing babies sucked a lot of the calcium and nutrients out of her bones while she was still growing herself. She is OK now, but we spent about $1,000 on surgeries, meds, and treatment.
I didn't know about that page, so what I did was call a lot of vets in my area and asked them "which vet would you recommend that has the most experience with guinea pigs?" When I kept hearing the same name over and over again, that's who I went with.