I have two cats that are around 10 years old and lately the one cat has been crying nonstop for wet food. We usually feed them 2 small cans and dry food through the day but the one cat has been crying so much I started giving her an additional small can a day. This still has not worked and anytime I am in the kitchen she is crying, nudging my leg and nipping my knee or ankle. My husband will feed her in the morning and when I get up an hour later she is crying again for more. Any idea what this could be related to and what to do ? Should I take her to the vet?