It's hard to tell from the pics, but I don't think she looks underweight. If she is, it doesn't seem like it could be by much. Look for signs of illness - nose running, eyes watering, always in a meatloaf position (hunched up - kind of like those pics). You know her and how she typically behaves, just start making note of anything you seem to think looks differently about her or her behavior on a regular basis.
Just make sure you see her eat. If you think it is less than normal, try giving her some Gerber Baby Meats Stage 2 (no additives like garlic/onion). Might be just enough to get her over 'the hump' if for some reason she is in a funk over a recent incident with another animal/cat.
How long have you had these cats around? It's either been a long time, or they have been abandoned by someone. Abandoned cats are skittish around people, but are much more inclined to hang out with their 'food supplier' once they learn not to fear them completely.
Just make sure you see her eat. If you think it is less than normal, try giving her some Gerber Baby Meats Stage 2 (no additives like garlic/onion). Might be just enough to get her over 'the hump' if for some reason she is in a funk over a recent incident with another animal/cat.
How long have you had these cats around? It's either been a long time, or they have been abandoned by someone. Abandoned cats are skittish around people, but are much more inclined to hang out with their 'food supplier' once they learn not to fear them completely.