There are Health Risks associated with keeping chickens (avian flu, samonella) and it is not recommended that children under 5 interact with them. Children should also always be supervised around poultry. Doesn’t sound like the best animal option for teaching about sustainability when they can’t interact with them because of the health risks?
Is there not enough disease out there right now with Covid?
Have a read what the SPCA has to say about the health risks https://spca.bc.ca/news/backyard-chickens/ and the Centre for Disease Control https://www.cdc.gov/healthypets/pets/farm-animals/backyard-poultry.html