For cooperative species, there can be great value in the synchronization of physiological states to coordinate group behavioral states. This is evident in naked mole-rats (Heterocephalus glaber), which have the most extreme form of cooperative breeding in mammals. Colonies have a single reproductive female, “the queen,” supported by up to hundreds of colony “subordinates” which are all socially suppressed into a prepubescent state. Subordinates cooperate in colony maintenance, defense, and alloparental care. Prior work has reported that there may be social sharing of hormones between individuals in the colony; when the queen is pregnant, subordinates of both sexes develop enlarged nipples, and female subordinates can develop vaginal perforation, though none of these animals are reproductive themselves. We sought to document hormonal changes behind these observations by monitoring queen and colony estradiol levels during and after pregnancy using non-invasive fecal hormone measurement. We found that both queens and colony subordinates increased estradiol levels during the queen’s pregnancy. We then tested whether treating a single subordinate in the colony with estradiol would induce the same effect in other colony members. The estradiol treatments raised the treated subordinate’s levels into the pregnancy range, but other colony members remained unchanged. This indicates that the social influence on estradiol levels is specific to the queen. We examine queen behavior and pheromones as cues for triggering this prepartum colony-wide increase in estradiol. These results have implications for how cooperative breeders coordinate alloparental care, and how social cues can influence individual physiology.