If the Labrador retriever is healthy the dog would have a nice shiny coat. The dog would also be very energetic and eat at least a bowl of food a day . The dog would also drink at least a bowl a day. These are the signs for a healthy Labrador retriever.
Some dogs lay around because they don't get enough stimulus or exercise. If you have any worries about your dog, the best thing to do is contact your vet, the only one who can give you a proper diagnosis.
If your dog's behavior has changed drastically, then it's probably time to take him to the vet. If he's just getting older, it might just be a sign of aging.
Energy level in dog will provide some indication of health, but the dogs age and environment will need to be considered. Also, looking at the dogs fur and weight are important when assessing health.
