Size: Is It Large Enough?

[LauraBean]

I once again got the urge to re-arrange the girls cage.
Previously, I had a 5x6 with a 2x3 hayloft. I changed the cage, making it 3x7.75 with the same 2x3 loft. The only support for the loft inside the cage is arranged in the center so the girls can still run laps if they want to. This comes out to somewhere in the neighborhood of 27.5 square feet (not including the adjustments needed to factor in the ramp)
Is this enough room for my six sows? I was trying to remember the formula for minimum square footage...is it 7.5 sq. feet for the first pig and 2 sq. feet for each additional pig?
Of course, I want more than the bare minimum for my furry princesses. I was just curious since I couldn't remember

[Ly&Pigs]

For sows it would be a 2x3 for 2 sows then an additional 1x2 space for each additional pig, for boars you'd start with a 2x4.

Your 3x7.75 is large enough.