Our lab Kona is completely nuts! She LOVES rocks of all things! If you are outside - I don't think you would see her without a rock in her mouth or her barking near a rock that she wants you to throw. It really does get annoying. She will bark consistently until you throw said rock. Seriously. If you have noticed in several of my videos you always hear Kona barking in the background! hehe! LOVE her to death though. Labs will be Labs I guess!
Proof.
She also loves fishing in the pond for rocks. NUTS!