bonding

Question
can you bond a pregnant guinie pig with a non pregnant guinie pig  and what will happen

Answer
Yes, you can bond a pregnant guinea pig with one that is not. If the expectant mother is far along in her pregnancy you might not want to put her through the stress of a possibly rough introduction.  Most often when you first introduce two new pigs to each other there's a day or two of poking, pushing and shoving on the part of the resident pig.  This usually doesn't mean blood or hair pulling.  It's just their way of saying, "I was here first, so I get to make the rules."

In most cases this behavior is short lived. Not all pigs go through this, some just accept the new roommate and don't make a fuss.  My experience has been that having them in separate cages where they can see and smell one another does nothing to lessen the introduction and make it easier.  That's probably due to the issue of territory. If they each have their own space that's THEIR space and they protect it. Once the barrier is down they have to decide who's going to be the boss.

Generally speaking two sows will work it out fairly quickly. You may see the new pig staying in the corner and being kept at bay by the senior resident.  That's normal too.  It's the newbie's way of saying, "I respect your reign and I'll give in to you."  In a short time seniority is established and everyone is happy.

I don't think pregnancy has anything to do with how calm or tough the introduction will be.  Expect the established pig to purr and strut her stuff when first meeting the new one.  Sometimes the tenancy issues are settled quickly and sometimes it takes a few days.  

When it comes time for delivery you don't need to separate the two sows.  Cavies are wonderful parents and will take care of each other's babies even if one has never had any.  I once had a sow that began producing milk and nursing the other sow's baby even though the she had never had a litter of her own. Their drive and instinct for motherhood is strong. They will not hurt the new babies.

The size of the cage makes a big difference.  There must be enough space for the new pig to get away from the other.  If it's a tight space they likely won't settle in well and the fighting may be violent.  

Be patient.  If there's serious fighting that's different, but in most cases it goes fairly smoothly.

Good luck to you.  Please let us know how it works out.