Old Dog doesn't eat ???

[Dean]

I have a 9 year beagle seemed to be in good health until started running this season. She hunts so hard when she gets in the kennel she doesn't want to eat. I'm useing the same feed I've been feeding (river run 24/20)with some can food mixed in. She will eat chicken or cooked food. I got sometype of syrup mixture with vitamins to stimulate her appetite from vet. but it has not wored as of yet! ANY SUGGESTIONS??? thanks Dean