Bird Birds are divided in the Mosaic law into two classes, (1.) the clean (Lev 1:14; Lev 5:7; Lev 14:4), which were offered in sacrifice; and (2.) the unclean (Lev 11:13). When offered in sacrifice, they were not divided as other victims were (Gen 15:10). They are mentioned also as an article of food (Deu 14:11).