Karen, I would say you are lucky. I have never seen a ram lamb NOT challenge. Just like the teenagers they are. Young, dumb and full of themselves. An old ram may or may not respond. Most dominant old rams , can "stare" most of these kids down, but some kids still need to talk sh-t and want to fight. Depending on old rams attitude will depend on how hard he hits the kid. And how stupid the kid is. On a rare occasion the kid strikes a lucky bkow and will kill ole guy. I have never had that happen. Usually the kid is killed if he does not submit. I also have not had that happen, but have seen that at several ops in my area. Most of them were In ops that penned mature rams alone and ram lamb got into enclosure or wrong pen at breeding. Most of those ops used to single pen mature Rams. Most now pen matures together and have less aggressive rams. I have penned ram lambs with matures, but the nutritional needs are so different ,that ram lambs were thin and old guys were fat.
It is funny to watch a "patient" old guy tolerate a pestering kid to a point. At some time the old guys has had enough and a staggering punch to the head,much like Rhonda Rousey endured , will change the kids mind as to who is boss.If not, a career killing blow will stop it at some point. Various breeds can be aggressive, and I trust none. I try to always have something in my hand to fend off any sheep that violates my personal space. A 3 foot piece of 1 inch plastic water pipe works nicely and makes enough noise and sting to keep them at arms length. And if I really lay Into one, will not do damage. Mostly I just cull them .