Ascaridia /æskəˈrɪdiə/ is a genus of parasitic nematodes. Members of the genus are primarily intestinal parasites of birds. Three species are well known, namely, A. galli found mostly in chickens, A. dissimilis in turkeys, and A. columbae in pigeons. Lesser known species such as A. hermaphrodita, A. sergiomeirai, A. ornata, A. nicobarensis, and A. platyceri are found in parrots. The eggs of A. dissimilis are marginally bigger than A. galli, and A. columbae is marginally smaller. All these ascarid eggs are similar in appearance to Heterakis gallinarum.