Ive seen deer droppings the size of my fist. (clumped up) Right in the vicinity of a huge rub. but I have also watched a buck drop his mess and it wasnt in clumps. I think from experience that the clumps of deer droppings are from mature deer that bed most of the day. I also think that it depends on what there eating. I check this out when scouting. The color of the droppings usually give ya an idea of what there eating. and the size of the droppings can give ya a reason to hunt an area......... Good Luck to all this year