Normal aerobic metabolic rates persist in the early chicken embryo following elimination of cardiac output, but the dependency of tissue growth and differentiation on blood flow is unknown in these early stages. We partially ligated (25-50% occlusion)the ventricular outflow tract of HH stage 16-18 embryos, producing a wide range of cardiac output. For the next ~48 hours (to HH 24), we measured heart rate (HR), stroke volume (SV), and cardiac output (CO), as well as these growth indicators: eye diameter, chorioallantoic vessel and body mass. Acutely, HR declined with partial ligation (108 beats . min^-1 to 98 beats . min^-1). Paradoxically, SV and CO decreased sharply in most embryos but increased in others, collectively producing the desired large variation (up to 25 fold) in cardiac output and permitting assessment of tissue growth over a very large range of blood perfusion. Eye diameter doubled (0.6 to 1.2 mm) with development from HH 16 to HH24, but within a developmental cohort there was no significant correlation between eye diameter and CO over a 25-fold range of cardiac output. Similarly, CAM vessel index was independent of CO over the CO range at all stages. Finally, body mass increase during development was not significantly affected by partial conal truncal ligation. Collectively, these data suggest that normal eye and vessel growth and body mass accumulation occurs independent of their rate of blood perfusion, supporting the hypothesis of prosynchronotropy - that the heart begins to beat and generate blood flow in advance of the actual need for convective blood flow to tissues.