Bones are a big 'no-no'. Please do not treat your pets with bones. Bones get stuck too often as your pet tries to swallow these.
Snacks and treats should be healthy and should not be given so often that your pet can gain weight from his/her snack.
There are various biscuits on the market that is a good option for a treat. It is recommended that you buy these from a veterinary practice as the vets only stock what they would see as a healthy option.