The present invention relates to a method for non-destructively identifying a characteristic of an Gallus Gallus domesticus embryo in ovo, the method comprising: (a) obtaining a sample of material associated with an egg comprising the embryo, and (b) measuring a score value for the presence of, and concentration of at least a first 5 biomarker in the sample indicative of the characteristic of the embryo, and (c) applying a threshold to the score value and concentration obtained in (b) to identify the characteristic for the embryo associated with the presence and concentration of the biomarker, wherein an at least first biomarker comprises an amino compound having a molecular weight in the range of from 140 to 190 g/mole.
