In the first phase of the current study, metabolic combinatorial solutions were in ovo administered in broiler eggs on Day 18 of incubation to investigate their effects in broiler chick tissue nutrient profiles until Day 10 of posthatch growout. In the second phase, the effects of in ovo injection of L-carnitine on Day 18 of incubation in broiler eggs were examined. The treatment solutions used in these studies were considered to play significant roles in various biochemical pathways, and were hence tested to determine whether they could potentiate the physiological growth and development of the broiler embryos and posthatch chicks. The in ovo injection of treatment solutions in both trials did not produce any significant increase in performance or slaughter yield in broiler chicks. However, positive trends were determined for rate of hatch and tissue nutrient profiles, which implied that the in ovo administration of nutrient supplements may be supportive of embryonic development and posthatch growout performance.