c&c cages are measured in grids not feet. So when we say a 2x4 we mean 2 grids by 4 grids
A 2x4 c&c measures 150 cm/ 5ft which is big enough for two piggies
A 2x5 c&c measures 180cm / 6ft and is big for three piggies (or two boars)
a 2x6 c&c measures approx 210cm / 7ft and is big enough for four piggies
a 2x7 measures approx 240cm / 8ft and is big enough for five piggies.
(I say approx because grids are generally 35cm, not 30cm, plus when the connectors are on it makes it slightly bigger - eg a 2x6, I think actually measures closer 220cm than 210cm)
a 2ft x 5ft would be the absolute minimum for three piggies. It’s because minimum welfare requirements are a 4ft (120cm) cage for two sows, you then add on a further 2sq ft for additional piggies meaning a 2ft x 5ft would be the minimum for three, but we recommend a 2ft x 6ft (2x5 c&c)