In Australia, the spectacled flying-fox (Pteropus conspicillatus) (SFF), is listed as ‘Vulnerable’. Many juvenile SFFs come into care at the Tolga Bat Hospital, a privately funded community organisation. The aims of this study were (1) to estimate postnatal growth rates for length of forearm and body mass; (2) to describe the association between body mass and length of forearm; and (3) to develop a milk feeding chart for infant SFFs. Cross-sectional data were collected for 2680 SFFs from the 2006–07 to the 2016–17 seasons. Forearm length increased by 0.55 mm and body mass increased by 1.5 g per day. Longitudinal data were collected during the 2016–17 season for 128 SFFs. According to these data, forearm length increased by 0.71 mm and body mass increased by 3.4 g per day. Both analyses indicated exponential associations between forearm length and body mass (P < 0.001). Reasons for the differences between the cross-sectional and longitudinal results might include the negative impact of tick paralysis in the cross-sectional study and the positive effect of human care in the longitudinal study. The proposed feeding chart is based on length of forearm. This study was established in a wildlife-care facility providing a model for similar work with other wildlife species.