Reproductive potential was assessed for stable fly cohorts fed cattle, chicken, or horse blood. Flies provided chicken blood oviposited 20% more eggs per day than did those fed cattle or horse blood. However, flies provided cattle or horse blood were fecund 50% longer. When both egg viability and number of eggs produced were considered, lifetime reproductive potential was almost twice as high for flies fed cattle or chicken blood than for flies fed horse blood. Maternal investment, which took egg production and volume into account, was higher in cohorts fed cattle blood (70 mm3) when compared with the other treatments (chicken = 54 mm3, horse = 55 mm3). This is the first report of stable flies producing viable eggs after feeding on bird blood. Results from this study in addition to field observations indicate that stable fly interactions with birds may be limited to relatively low risk scenarios.