If you do a search on the forum, you'll get a lot of info on this - basically pregnant piggies are extremely pear shaped, usually - ie, they are 'nomal' sized on the head end, then get very round on the back end. From above they look like they have large lumps on either side near their back legs.
If you are feeling movement, it is most likely babies. You feel movement starting around 3 weeks or so before birth.
I'd recommend taking to a cavy savvy vet though, just to make sure. Other things can cause a distended belly that isn't pregnancy.
Good luck. If you can post pictures, especially a view from top looking straight down, that might help. Many of us here got the baby bonus when we got females that were already pregnant, either from a petstore before we knew better, or from a rehome/rescue where the sow had been in with boars at some point.
If you adopted her from a reputable rescue/shelter then I doubt they would house sows and boars together as they would effectively be adding to the overpopulation issue that we have today, and further so increasing their own problem, as a rescue/shelter.
Take her to a professional exotic vet, they will be able to tell you if she is pregnant or not. You may be feeling ovarian cysts as a pose to babies.
This is Gracie and in this picture she was pregnant. There's a possiblity that she is pregnant just make sure that she just doesn't have the chubbyness. Because one of my piggies I thought was pregnant but it was just because she was chubby in that area. But the picture is the one where she wqas actually pregnant. If you feel and see movement and if you lightly feel her tummy and it's harder than normal I would say say yes she's pregnant. How long has it been since you got her from the rescue? Because when you start to hear teeth grinding you got maybe a week or two left. But goodluck with everything.
I'm sorry, I don't understand- are you or have you been keeping her with the boar? Or are you worried she was with boars at the shelter? Most shelters are very good at sexing piggies and wouldn't have a boar and a sow together. If you are keeping them together, though, then there is a 99% chance she would be pregnant by now. It's pretty simple.
So the sow and the boar were together? You keep avoiding answering this question. I assume they were together, chances are, if this is infact true that the sow is pregnant.
How old is your sow? Are they still together? Was either spayed/nuetered?
I highly doubt that a shelter/rescue would put boars and sows together knowing the results of doing so. I am confused, you brought a boar then went an adopted a sow, and placed them together. That doesnt make sence, firstly why would a rescue/shelter adopt out to someone that was going to house a boar and a sow together unless one or the other was nuetered/spayed and secondly why would you put a sow and a boar together, period?
Well then, your answer is pretty darn simple, isnt it? You knew what gender they both were and you put them and are still housing them together. Is it not obvious that the sow is now pregnant? Is it not obvious that this forum condones backyard breeding or any breeding that does not better the species? Is it not obvious that you have and continue to put your sow at risk of death? Is it not obvious that you are now contributing to the overpopulation problem which overflows the rescues and shelters?
Perhaps you should read this site http://www.cavyspirit.com/breeding.htm. I am sorry if I come across as being angry, as I am, and the reason behind this is that everyone, myself included is trying to solve this overpopulation problem and people (now you included) are adding to it by recklessly breeding not to mention the pain and trauma that the sow is put through and thats if the sow survives.
Based on your past posts, your adopted sow is two years old. Unless by some chance she has had a litter in the past, her hip bones have already fused and she will be incapable of giving birth to a litter successfully. Unless you schedule a C-section to have the babies removed, she and the babies will die. Even with the surgery she and the babies are at high risk. Do you realize you just put your guinea pig's life in grave danger? You need to get her to a vet. Why did you put those piggies together? You adopted them to save their lives, but by breeding them you are effectively canceling that out and adding to the overpopulation problem. Not to mention the fact that you decided to do so with very little knowledge about guinea pigs, and have needlessly endangered the life of your sow.
I agree with what envisionary and pigs said. What you did is very irresponsable. Why? Even after you came here, you didnt remove them? I can semi-understand ignorance before coming here, but not after.
Well, this just gets worse. Most likely your sows pelvic bones have fused, this means that the babies can not come out naturally and a C-Section is needed. If she does not have a C-Section then she will die and so will the babies, if she does have a C-Section then she will probably still die as the risks of this operation are high. Do you understand what you have done? Your sow is now at a high risk of death, when she didnt need to if you hadnt of selfishly put your boar in with her.