One is fat, yes
One is thin and wirey
They eat the same shit, so I guess its just genetics
A friend of mine realized the fatter one was eating more then the other.
Fatter one is also the smarter one, smaller one is as smart as a lobotomized cockroach. Fatter would eat the food while the lobotomized was messing around playing games with ghosts.
They are not small though, smaller one was 5.5 kilos, fatso 6.5.