Comment by elcritch
Chicken "sexing" is a fun example of how expert knowledge can be transferred without either expert or novice being able to explain it:
Chicken "sexing" is a fun example of how expert knowledge can be transferred without either expert or novice being able to explain it:
I've read that birds used to have penises (and paleognaths and waterfowl still have them today), but the Galliformes (including chickens) developed atrophied penises which are difficult to see (hence chick sexing and feeding males to the meat grinder), and the Neoaves lost them entirely. Though https://prumlab.yale.edu/sites/default/files/brennan_etal_20... suggests the exact nature is more variable between birds in lineages that "have" them