The cost of reproduction is thought to be a major regulator of life-history evolution. Increased investment in reproduction is thought to come at the expense of self-maintenance, and thus limit parental lifespan. The regulation of the balance between reproduction and self-maintenance is still poorly understood, but investment in reproduction is predicted to come at the cost of immune function. In birds maternal investment in egg components is energetically expensive, and large variations in the level of maternally provided resources have been documented in natural populations. In wild populations, the limited availability of nutrients and other recourses is often suggested o mediate life-history trade-offs. Here we examine the evidence for a reproduction-immunity trade-off at the transcriptional level in the absence of resource limitation in a captive population of Japanese quail (Coturnix japonica) divergently selected for high versus low maternal investment in egg size. As all animals shared a resource-rich environment, any trade-offs between reproductive and immune investment are more likely to be related to intrinsic factors than to external resource availability. Using whole-transcriptome RNAseq, we identified 30 consistently differentially expressed genes in ovarian follicle cells in two replicates of the high and low maternal investment lines. In the high maternal investment line genes associated with reproductive investment are upregulated, while genes linked to immune function were downregulated. Our data provide experimental evidence for an intrinsic reproduction-immunity trade-off in the absence of resource limitations in a precocial bird.