Grebes have a unique feather-eating behavior, but there are many suspicion and dispute on the mechanism of the digestion process and the function of feathers in the digestive tract.
??目鸟类有独特的食羽行为，但对进入消化道后羽毛的功能、消化机理等存疑及争议颇多。
2
Men who have gone half a year without eating chicken will start drooling copiously at the sight of even a feather duster.