As long as your piggies still have each other and their familiar cage and routine they should be fine

They will probably be very excited and pleased to see you when you come home, I remember the first time we went away a few weeks after getting our first 2 piggies and leaving them with a boarder- they still hadnt fully bonded with us when we went away for a long weekend as we'd only had them a month, but gosh were they pleased to see us when we got back!
Now if we go away I usually pay my daughter to piggy sit at our house as 8 indoor piggies are too many to board, and we just have to accept that while my daughter is very kind to them she completely overfeeds them (the piggies know her as "apple lady" because she has been known to give them almost a whole apple each!) but long term it does no real harm and we are very strict with the veg when we come home.
Have a lovely trip, it sounds like your piggies will be in safe hands! X