Effects of the in ovo injection of commercial diluent containing supplemental microminerals (Zn, Mn, and Cu) on hatchability and hatching chick quality variables in Ross × Ross 708 broilers were examined. On 17 d of incubation (doi) eggs were subjected to 1 of 4 treatments using a commercial multi-egg injector. Treatments included non-injected (treatment 1) and diluent-injected (treatment 2) control groups. Those in treatment 3 received diluent containing 0.181, 0.087, and 0.010 mg/mL of Zn, Mn, and Cu, respectively, and those in treatment 4 received diluent containing 0.544, 0.260, and 0.030 mg/mL of Zn, Mn, and Cu, respectively. A total of 1,872 eggs were distributed among 4 treatment groups on each of 6 replicate tray levels. Hatchability of fertile eggs set (HF) was determined on 20.5 and 21.5 doi. On 21.5 doi, HF and mean hatching chick weight (MHW) were determined. One bird from each treatment replicate group was randomly selected, weighed, and necropsied for the extraction of their livers and tibiae. The tibiae fresh and dry weight, length, width, bone breaking strength (BBS), and percentage of bone ash (PBA) were determined. The dry livers were weighed and ashed. Injection treatment had no significant effect on HF at 20.5 doi. However, there was a significant injection treatment effect on HF at 21.5 doi. The HF of eggs at 21.5 doi in treatment 4 was significantly lower than that of the non-injected control group, with treatment 3 being intermediate. Furthermore, there were no significant treatment effects noted for MHW fresh and dry tibia weights, tibia length and width, tibia length to weight ratio, BBS, liver ash content, or percentage of minerals (Ca, P, Mg, Mn, and Zn) in the tibia ash. However, embryos from eggs that received treatment 4 had a significantly higher PBA in comparison to all other treatments. In conclusion, although treatment 4 negatively affected HF, the injection of diluent containing the high micromineral concentration has the potential to improve bone mineralization.
