Matthew Davies emerged remarkably well from his ordeal after being rescued from the isolated area at Llanddew, near Brecon, in Wales.
The youngster, reported missing last Saturday evening, became trapped when one of his legs disappeared into the quagmire, police said.
His cries for help were finally rewarded yesterday when he alerted a man out walking his dog. Firemen took two hours to free Matthew, who was taken to Brecon War Memorial Hospital suffering from exposure and hypothermia.
A spokeswoman said: 'His condition is satisfactory. He is now being slowly rewarmed and fed, and will be kept in for a couple of days.'
A spokesman for Dyfed-Powys police said: 'Considering the length of his ordeal, he is in remarkably good physical condition.
'It was a real stroke of luck that he was found. It is an isolated area and he could have been there for much longer.'
Matthew's mother is at his bedside. The family lives in a caravan at the Royal Oak pub in Llanfihangle Talyllyn, Powys.
A police spokesman at Brecon said: 'We are still trying to establish just how long Matthew had been trapped. We will be talking to him as soon as he is well enough to tell us what happened. It seems he was strong enough to be shouting for help when he was found by the man walking his dog.'