So we adopted a 6 year old Jaxk Russell who is very sweet and lovable. He loves walks but when we get home he is quite happy to sleep most of the day. Also my husband took him on out and rode his bike, the last half of the ride my husband had to get off the bike and walk cause the dog flat out refused to go if my husband was riding. My husband thought he was going to have to carry him home. Is this normal for a Jack Russell? Could it be he is not used to exercise?

I would say he's not use to that type of exercise.

Also, check his pads. Not all dogs have rock solid pads. He may have skinned his feet.

Take your time introducing dogs to exercise. The majority of them can handle it if introduced slowly and correctly.

I'm sure you didn't ride 5 miles at break neck speed first day out on your bike, don't expect the dog to either.