When Conan is shackled to the Wheel of Pain as a child other slave-children are as well, but years later Conan is pushing the wheel alone. Did the other slaves die? Were they sold off over time?
The film's official novelisation (based on the screenplay) indicates that the other slaves on the wheel were worked to death or possibly taken to slave elsewhere.
So Conan and his fellows laboured day after day, month after month, until time lost all meaning for them. Faces slack, eyes dull, hearts emptied of emotion, time for them contracted to the present moment only. Yesterday was mercifully obliterated from their consciousness; tomorrow was a nightmare yet undreamed. When a wheel-slave fell and could rise to toil no more, the Master summoned the ever-present Vanir guards with a curt gesture to unshackle the gasping body and bear it off—no one knew where.
Conan dully wondered at times if that was how the Vanir fed their dogs.
The seasons changed; months stumbled into years. Wheel-slaves died, only to be replaced by other slaves, reaved by the Vanir raiders. Some of the new captives were youths and men of Cimmerian stock; others were golden-haired boys from Asgard: a few were gaunt Hyperboreans with limp, flaxen locks and, it was said, a knowledge of sorcery. Not that it seemed to do them any good.
For the record, the others from his village were sold off immediately.
As for the captive women and girl-children of his village, they were led away to face a different, perhaps even uglier fate. Conan never heard of them again.