Chulin 23 - Intermediate Stages of Birds, Lambs, and Dough
If the feathers of a turtledove or a pigeon started yellowing, the turtledove can't be sacrificed because it is too young, and the pigeon - because it is too old. Rabbi Zeira asked, "Is this for sure or out of doubt?" Meaning, if one promised a bird burnt offering and then brought a turtledove and a pigeon with yellowing feathers, is at least one of them valid, or, because it is a bird in a class by itself, neither is valid?
Try this answer: the Torah said "sacrifices … from birds," and this means that some birds are excluded. Which ones? Isn't it ones with yellowing feathers? - No! Excluded are birds that were sodomized or worshiped, and Rabbi Zeira does not get an answer.
He asked a similar question about sheep. A sheep younger than twelve months is a lamb, one older than thirteen is a ram, what is its status in between? Does it require libations like either a lamb or a ram, or is it a separate creature with no libations? Again, no answer. He also asked about dough in intermediate stages of leavening, can it be brought as part of a thanksgiving offering.
Art: Antonio Paoletti - Feeding The Pigeons At Piazza St. Marco, Venice