In prior studies it was shown that the growth of turkey embryos was dependent upon maternal dietary iodide as well as genetic selection. The current study posed the question of which organ systems respond to these variables. Embryos from lines selected for 16-wk BW grew at the same rate as unselected embryos from the randombred population serving as the initial source of the selected line until approximately 21 d of incubation (selected = F; randombred control = RBC2). Line differences in growth of F embryos could be accounted for increased liver and heart growth at the expense of muscle growth. Muscle growth increased in the growth-selected line prior to pipping. Muscle growth was affected less when dams were selected for egg production (selected = E; randombred control = RBC1). Muscle growth was slowed in E line embryos compared to that of RBC1, and liver and heart growth were slowed at internal and external pipping stages in E embryos compared to RBC1. Early muscle growth was augmented when F dams were fed supplemental iodide. A similar response was observed in E line embryos but occurred at a later stage of development. Measurements indicated decreased tissue glycogen in liver, heart, and muscle of selected lines may be one possible mechanism by which growth or organ function may come in conflict.