The youths, aged 11 and 14, set upon the helpless animal – nicknamed “Little Man” by neighbours – in Hayton Close, Sunderland, on 10 September.
Their attack was witnessed by a local resident who rushed out of her home to find the hedgehog suffering from serious injuries.
It was taken to a nearby vet but had to be put down because it was suffering from severe respiratory distress.
Police investigating the attack later discovered videos of animal cruelty on one of the boy’s phones.
The films included the youths encouraging a dog to fatally injure a rabbit and pigeon chicks.
On Thursday both boys pleaded guilty at South Tyneside Magistrates’ Court to five wildlife offences including causing unnecessary suffering to an animal, cruel treatment of a wild animal and killing a wild bird.
The boys have been referred to the youth offending team and one of the sentencing options is re-education through volunteering at a wildlife charity.
Wildlife officer PC Peter Baker, of Northumbria Police, said: “We are a nation of animal lovers and there can be little doubt that the boys’ behaviour is barbaric and totally unacceptable.
“These investigations are never easy, and it is clear that the two individuals not only showed a total disregard for the welfare of these animals, but also took a degree of satisfaction from filming their criminal activity.
“They might not have given a second’s thought to the potential consequences of their actions that night, not to mention the unnecessary suffering that they caused to a number of animals.
“However, they now have criminal records that will be with them for the rest of their lives, and can both count themselves lucky that they have avoided a potentially more severe punishment due to their young age.”