You aren't crazy I know exactly what you mean. Winter is skinny and she gets the same amount of food as Smudge and here's actually a higher fat content but she's as skinny as a rail...or as people say she looks underweight but she really isn't she's actually the ideal weight at least for her.

Tama's really skinny as well, in fact we have to try to put two more pounds on him because he's a little to skinny. So I really do know what you're talking about.