I have papers that state these guys are 2-4 years old. I’ve not had a chance to look at teeth but horn growth doesn’t reckon up with my experience. They’re nice though.
The teeth are key. There are no upper incisors, so you need only to see the bottom gum.
Rule of thumb..... Look at the the midline of the lower jaw....if there's no permanent teeth to either side of the midline....under a year old. One permanent incisor to either side of the midline = 1 year old, 2 permanent incisors to either side of the midline (i.e 4 permanent incisors in total)= 2 years old, 3 permanent incisors to either side of the midline (i.e 6 in total)=3, 4 permanent incisors to either side of the midline (i.e 8 permanent incisors in total) = 4 years or more year sold. 8 permanent incisors is the total they get and is also know as a 'full mouthed' sheep. As they get older then gum recession occurs a.k.a 'long in the tooth', tooth breakage ('broken mouthed' or 'brokers') and may even end up with total tooth loss due to breakage and caries, when they are known as 'gummers'. Sheep still do pretty well without incisors as long as they have grinding molars left.
I was always under the impression that those "knots" in the horns were like tree rings... or rattles on a rattle snake (one per shed)... one per year of growth. So that being the case, those two big boys up front would be 6-8 years old.
Horns don't grow evenly across the lifespan of the sheep, they grow much faster the first couple of years. It looks like you got a handful of lambs there but the big horned boys could be 2-4 if they're from a line bred to put on a lot of horn fast. Check the teeth for sure but as long as the tags match up I'd buy that age.
The guy up front with the scrape on his nose has 3, maybe 4, big ruts in his horns where he was a little run down, probably he was breeding or it was winter and not getting as good nutrition. That would support him being 4-ish and just being bred for horns that grow rapidly the first few years. You can also see how much growth happened between the tip and that first rut compared to the growth between the following ruts.