A group of Orpington primary school pupils are "deeply hurt" after the school's chicken coop was ransacked and the four chickens it housed stolen.
The chickens disappeared overnight from the garden of St Peter and St Paul Catholic Primary School, St Paul's Wood Road, last Thursday (June 12).
The school's devastated pupils won them, alongside school catering company Eden, in a borough-wide competition promoting healthy eating in May.
The birds are 17 weeks old and have only been at the school since June 3.
Headteacher Joanna Seymour described the event as an "act of vandalism" and said the loss of the poultry - named Petra, Paula, Theresa and Bernadette - was "tragic".
She added: "The children had worked hard with the school catering company Eden and won this fantastic prize to support their learning.
"During the night cruel vandals broke into the school grounds, smashed the hen house and took the chickens.
"This mindless act has upset all the children who had worked so hard for their prize, naming them after the school houses and taking responsibility for the care and feeding of them.
"They were far more than just school pets, they were a key feature of the children's outside learning and play.
"The vandals have created a very sad atmosphere in the school and the children are deeply hurt by their actions."
A police spokesman said: "Police are investigating a burglary that occurred overnight between June 12 and 13 at the St Peter and St Paul Primary School, St Paul’s Wood Hill, Orpington in which a hen house was damaged and four chickens stolen.
"No arrests have been made to date and enquiries continue."
Anyone with any information should contact Bromley police on 101 or crimestoppers anonymously on 0800 555111.