So my tractor is pretty big and heavy already. We can move it but it is hard. We are using pine pellets right now which I like except for the price. We change them out every two weeks and that is $12 every two weeks. If we used sand it would probably make it impossible to move with the weight of the sand. I don't know if shavings would be cheaper but I think we would have to change them out even more often because water does get into the coop--through all the ventilation that is necessary for our terrible heat! So what else is left? Maybe I don't have any choices???