Adults of Fannia canicularis (L.) and F. femoralis (Stein) were given a choice of poultry manure of 25, 35, 45, 55, and 65% moisture for oviposition. Adult F. canicularis laid most eggs on 55 and 65% moisture manure, whereas adults of F. femoralis laid most eggs on 65% moisture manure. Few eggs of either species were laid on manure ≤45% moisture. Larval development trials were conducted at 33, 40, 47, 52, and 56% manure moisture, noting number emerged, time required for emergence, and adult size. Neonate larvae of F. canicularis developed well at moisture levels ≥47%, some developed slowly and into smaller adults at 40%, whereas 33% moisture was lethal. Manure moisture of 40–47% depressed emergence and slowed development of neonate F. femoralis larvae. Early third instars of Fannia spp. were more resistant than neonate larvae to low moisture conditions. Some third-instar F. canicularis could survive and emerge at 33% moisture, whereas some third-instar F. femoralis could emerge at moisture levels of ≥40%. Overall, F. canicularis tended to use drier manure for oviposition and could develop in lower moisture conditions relative to F. femoralis. Implications of these moisture requirements for management are discussed.