You should be able to get a gentle leader for a rottie, it all depends on muzzle size and if I remember correctly I saw some large breed sizes when I was shopping for one for Winter (can you believe she's a size 1) She's a very pretty dog though...You're right though she does seem a tad on the heavy side, well at least from the side view of her, there's not enough tuck. If you can't feel her ribs she's overweight