Hi our 16 year old cat is healthy but has lost some weight. The vet said it might be due to fact I changed her dry food recently to senior food and to change back to Whiskers cheaper brand which is what she's used to. She also gets cooked chicken every day. Any other ideas what I can do to help her put on a wee bit of weight? Vet isn't concerned at the moment and says it may be due to her age as she's still active and goes outside. I also put salmon oil on their dry food. Thanks