well try not to reference modern items.
That stood out like a sore thumb.
ie: the size of a dime.
A man's thumb or finger nail, would be a better comparison.
15 paces would be reasonable, far enough to be difficult but near enough to be doable with a lot of practice.
It depends on whether the girl is supposed to be preternaturally skilled, or just skilled.
If you're looking for just europaen myths and sling tales, then fine - but there is a rich vein of slinging stories and genuine historical sling usage in indian history and mythology.
The more I learn about it, the more I'm amazed of the overall ignorance of indian sling usage in the western world.
did the romans get as far as india ?
Probably.
Also it's far more likely for the girl to be herding goats, rather than sheep.
Goats were by far the most commonly herded animal in the ancient world, and in fact are still the most commonly herded animal in the world today.
not sure how big a robins egg is, but for me 35-40mm is an ideal size for a clay ball.
weight is 50-65 gms. Also an ideal weight for me.
A lot of people like larger and heavier missiles, a lot depends on the sling design.
Balearic slings tend towards being quite stiff and small items don't work well with a split pouch.
Shepherds slings, on the other hand tend to be more lightweight and flexible and significcantly more versatile - as a herder has a variety of tasks to use a sling for, and different slings for each task makes little sense.
So a lightweight sling with a solid leather pouch just makes sense.
A sling would have been used to direct and herd the flock, as well as ward off predators and also used for hunting.
Dogs, back then were rare, and used primarily as protectors, they weren't used for herding.
Again - depending on which part of the world you're in - the turkish Kangal, is a large herd protector that dates back to and beyond roman times.
They were mainly for protection against predators, but also stopped poaching.
There are a number of tales of people inadvertently straying through the territory of a kangal pack, and the sudden appearance of an enormous yellow golden dog.
And if you see one in front of you, odds are there are two behind.
A slinger with a pack of kangals, would be one of the most succesful herders of their time.
Edited: Pella (Greek: Πέλλα) is an ancient city located in Central Macedonia, Greece, best known as the capital of the ancient kingdom of Macedon
So yeah, kangals or kangal type dogs.
This pictuire is a small man and a large kangal.
The average male kangal weight is around 140lbs.
They've been clocked at 30 mph - presumably by someone trying to get away from one by car, lol
Given that roman soldiers would most likely not ask or pay for a kid or lamb, being in an area where kangal type dogs were common, would encourage them to pay for the lamb/kid and not attempt to simply steal one.