Depigmentation of the eggshell
The color of the eggshell depends on the concentration of some pigments called porphyrins deposited in them. Such pigments are produced by the liver during the degradation of hemoglobin from red blood cells destroyed. Some toxics to birds such as nicarbazin , and others antiparasitics can damage the liver of birds (photo # 1) and affect the Normal production of porphyrins. Consequently the shells of the eggs appear with diferent color intensities and uneven pigmentation spots (picture 2). These changes occur suddenly and particularly frequent in hot seasons.