With no information on how your animation is set up, it's hard to give a definitive answer.

For the collider to match the object and move with it, you should see if your model consists of multiple meshes or bones. If so, you could make several box colliders on your bones or meshes that roughly match the shape of the object / bone. Then they will move, rotate and scale along with their game objects.

If you did not use bones and just a single mesh in blender in the first place, I would advise you to rework the animation for your unity project.