I really don't get, why he wants to expand to be able to house 250 Ferrets. He's not a breeder (debatable), zoo, etc. As he says. It's a RESCUE and from what I know their job is to rescue the animals and if possible find them new homes.
Also the only way for there to be 250 Ferrets in his vicinity that need rescue, is for him to hoard the Ferrets, forcing people to buy "new" ones. The way he runs his rescue, is actually contributing to the fact that more Ferrets need to be rescued.
He has all the supply, but doesn't answer to the demand (like 2 people that are just like him I would wager).