The two men and a woman aged between 20 and 22 from Rugby, had all denied her murder at Warwick Crown Court.
Ms Hayter, whose body was found by a jogger, was asked to drink urine and beaten to death, the court heard.
Daniel Newstead, 20, Joe Samuel Boyer, 18, and Chantelle Franklyn Booth, 22, all of Little Pennington Street, were all convicted of murder.
'Bloodied and abused' Jessica Lynas, 19, of Little Pennington Street, and Duncan Edwards, 19, of Ashwood Court, were found guilty of manslaughter.
All five were convicted of assault occasioning actual bodily harm.
End Quote Right Honourable Lady Justice RaffertyShe was beaten to death after being weakened by events in the flat”
Summing up the Crown's case, the Right Honourable Lady Justice Rafferty said: "The Crown said Gemma Hayter was asked to drink urine, she was bloodied and abused and violence was the next bedfellow.
"The girl spoilt their evening. They walked her the wrong way home for half an hour down a dark path. No one went down there for innocent reasons.
"She was beaten to death after being weakened by events in the flat. They (the defendants) went to Coventry hours after a girl lay dead."
Ms Hayter's body was found lying face down on a grass verge by a jogger while out on an early morning run.
In summing up the defence case, the judge said Newstead accepted he had struck Ms Hayter across the face because he was angry that she had made a mess of the flat they were in.
She said Duncan Edwards accepted he urinated in a can which was later given to Ms Hayter to drink.
'Incredibly difficult' Speaking after the trial, Det Ch Insp James Essex, of Warwickshire Police, who led the murder investigation, said Ms Hayter was killed in a "brutal attack".
"She was a vulnerable young woman who put her trust in people who she considered to be her friends," he said.
"Those people betrayed her."
He said her family found aspects of the court hearing difficult to cope with.
"They have been strong in their determination to seek justice for Gemma and I hope that now the trial is over they can begin to rebuild their lives," he added.
Ms Hayter's family, who issued a statement through the police, said her vulnerability led to her death.
"Our Gemma was a very loving and vulnerable woman who trusted everyone and her trusting nature and vulnerability led to her death on August 9th last year.
"Our family has found the last year, and especially the last seven weeks, incredibly difficult and today we welcome the jury's verdict."
The jury of seven men and five women took almost two days to deliver its verdict.
The five will be sentenced at a later date.