yes young bucks will rub. the main reason bucks rub is to get the velvet off their antlers when it starts to itch. its the same reason you scratch an itch. it feels good. they probably dont rub as much as a big buck because they dont have as big an itch. as for small bucks staying together. i have noticed this too. i think they may run together just because they are young and they feel more comfortable in the company of other deer.