The felters included Mahora teacher Robyn Perry and teacher aid Charlotto Ayto and Mr Willoughby's mother Kathryn.
"There were plenty of questions from the children, because many had never touched wool before," Mr Willoughby said.
Mr Hales told the Dannevirke News he was delighted with the response from the school children.
"There were some pretty happy children at the end of the day and the impact of this is quite dramatic in the learning environment," he said.
For the children, there was great excitement as they began making their own slippers.
"Robyn [Perry] demonstrated the very first steps of feathering out the wool to create the first layer and how to wet the wool to create the felt," Mr Willoughby said. "The noise level began to rise as wool, water and children all mixed together, but layer, by layer, the slippers began taking shape. And although the morning tea bell rang, not a child moved from their work. Water covered the bench tops, floors and the children, but finally the first stage was complete and each child had a wet, sloppy, semi foot-shaped clump of wool in front of them."
Each child from Team Tekau had a senior student working with them.
"Every child then popped on their slippers and the seniors began the task of moulding them to their feet," he said.
"The seniors worked hard to make sure each slipper was moulded perfectly and the Team Tekau children were becoming extremely proud of the new slippers being custom made in front of them. With the home time bell not far away excess water was squeezed out and finally the children were at the last stage.
"Moments before the bell rang, 22 children with huge smiles stood proudly holding a pair of custom-made felted slippers they had created."
Mr Hales said the slipper project will be one of the features of the exotic sheep shearing day to be held at his farm in September.
"They look pretty good and we hope to run the project for schools again next year," he said.