Lassie - Episode #98 - "The Nest" - Season 3, Ep. 33 - 4/21/1957

Lassie discovers a nest with a pair of western band tail pigeons is tucked into the working mechanism of the field mower and Jeff and Porky want Gramps to refrain from using it until they can safely move the birds without endangering the soon-to-be-hatched eggs.
Lassie and the Lassie Trademark are owned by Classic Media, which is owned by Dreamworks Animation.This episode was
broadcast (over the air antenna TV) by NBC affiliate COZI TV in 2014.