The horrific gang assault, which is believed to have been partly videoed on CCTV, took place on a park bench on Wednesday night.
The bench in Queen's Park on the outskirts of Bolton, Greater Manchester, has now been removed by police.
Earlier a forensic team searched the area around it. The boys, who cannot be named for legal reasons, appeared before Bolton magistrates court.
The youngest is 13 and the eldest 17.
Two brothers aged 17 and 16 were remanded in custody. The 13-year-old boy was remanded into local authority care and two 16-year-olds were granted bail.
Rachael Walsh, defending, said the boys would all contest the allegations. They next appear at Bolton youth court on Wednesday.
After the attack, the girl was taken to St Mary's sexual assault referral centre in Manchester for treatment.