Im worried about Spike (terrier ) who was 11 last August. He is loosing weight and is not eating the same portion size of food as he used to and im just wondering if his appetite is decreasing due to old age. Iv chopped and changed his food thinking that he might be tired of his usual but it has made no difference . He got all good in his recent health check so im a little puzzled as to why, however he is a food guarder and if he think Roge might get it he will finish it or stand over it. Any thoughts ??