She expected an SPCA inspector to look at the case on Saturday.
In a case like this it was possible the SPCA would involve the police or social services because research showed animal cruelty often led to abuse against other people later in life, Midgen said.
A Year 11 student, who asked not to be named, spoke to the Herald about the video.
"We were in class and someone got sent the video of him. Pretty much he kills the bird beforehand and then he rips it straight in half," he said.
The student had heard the bird was killed with a stone and then the boy "put its feet under his own feet and then pulled its wings".
"It was disgusting."
The student said the incident may have taken place near the school, as there were plenty of pukeko in the area. A group of boys were believed to have watched things unfold.
"In the video it showed him laughing, so he found it funny."
People had been sharing the video in private messages on Facebook, but the college had allegedly asked everyone to delete it, the student said.
"They told any students who had it, had to delete it off their phones or they'd be disciplined.
"They called in all the boys involved [in the initial incident] and anyone who had been sent the video they told them to delete it and let it go."
Principal Karen Brinsden said a concerned student bought the video to staff's attention earlier this week.
She said they spoke to the student in the video about the incident, which she described as a shooting expedition.
He told them the bird was shot and the video showed him "breasting" the bird in preparation for cooking.
Brinsden believed the bird was cooked and eaten.
She said since the incident took place on a rural property outside school hours there was no reason to take any course of discipline.
"As a school we do not condone cruelty to any wildlife or animal."