Pathogens are spread throughout the hatcher, again helped by the high air speed, resulting in high risks for cross contamination. In order to combat
pathogens, disinfectant (still quite often formaldehyde) evaporation is widely used during the hatching process. Formaldehyde is known to be a highly effective disinfectant. Formaldehyde, however, also affects the cilia and epithelium of the airways of the chickens, which reduces their capacity to filter out dust particles and creates possible entry routes for pathogens. Recent studies show that exposure to formaldehyde negatively affects body weight gain in the first week of a broilers' life.