Assertion: pigeon's crop milk | /r/CreatedBy | their parents
Facets:
Source sentences:
text: In the wild, newborn pigeons feed (only) on the crop milk produced by their parents.
text: Baby pigeons are called “squabs,” and are fed crop milk that is produced by the parents.
text: The first foods that baby pigeons consume are pre-"crushed" and semi-digested by the enzymes present in the crop milk produced by their parents.