My kingsnake quit eating about 2 and a half months ago. It is about 2 years old and 48 inches long. I normally feed it frozen mice between 3 and 5 a week. Last year around this time it quit eating but for only about a month. It doesn't seem unhealthy, it crawls around and is lively it just isn't interested in eating. It is losing weight but isn't showing any backbone or ribs. Any suggestions.