"4 feline house" I must agree with you on the desexing issue. There is simply no excuse not to, for both males and females. However...

I think saying that cats are almost unable to take care of themselves in the wild is not particularly true (excluding indoor cats). Most cats will bring home prey like birds and rodents and will eat insects, obviously not as much as they would in the wild - but why should they if they are being well fed, perhaps apart from curiosity. Cats are superbly adaptable and very much able to take care of themselves which is precisly why in many countries feral cat populations are almost out of control. They can adapt to anything from Australia's deserts to the almost arctic conditions of nearer the north and south poles. Many breeds have not been domesticated for a millennia and can still be found in the wild.