The only meat on the menu at the primary school is halal - where animals are controversially bled to death.
Children at four schools in Reading, Berkshire, have been eating these meals without parents' knowledge, the council admitted recently. The fact emerged after pupils were given letters from canteen managers to take home.
Islamic law insists on halal meat, produced by slashing an animal's neck with a single cut. Animals are not stunned beforehand.
Parents are furious at the revelation. One said: "I have nothing against halal meat - especially for religious reasons - but my daughter is Christian not Muslim."
A council spokesman said: "It became clear following the introduction of the new school catering contract with Scolarest that some parents might not be aware.
"Letters have been sent home. We are increasing options and offering fish each day."
Scolarest said: "We provide halal meat in four Reading schools at their request."