By no means am I any expert. My photo above is of one of my younger buff geese…it has a “normal” keel.
The goose below is a Buff Dewlap Toulouse with a more “pronounced”
keel and is also sporting two
lobes.
View attachment 3930883
I think it’s confusing also, birds with prominent keel are not necessarily emaciated. Some breeds have been line bred to achieve that shape. And as was mentioned, lobes can remain on an emaciated goose and shouldn’t be the sole basis of healthy body condition.
All goose breeds are a little different size-wise but if you feel the bird , the breast meat around the keel should be present. If you feel skin and bones and hardly any breast meat, then that goose is way too skinny,IMO, regardless of breed.