If the bag says food grade (Perma Guard Fossil Shell Flour is Food Grade DE, for example), then it is, but also check the silicon percentages. If 85%, it's for pool filters and dangerous to sprinkle around your birds. I had a feedstore tell me they carried Food Grade, but were out of it. When it finally came in, it was a 2 lb bag of 85% silicon dioxide, very disappointing. Prices vary widely on food grade, but if it's too cheap, I'd be skeptical.