Ved brug i praksis overføres passiv immunitet under æglægningsperioden i 43 uger efter sidste vaccination af de kommende æglæggere (broiler breeders), hvilket resulterer i at den passive immunitet varer mindst 14 dage efter klækning.
Under field conditions passive immunity is transferred during lay for 43 weeks after the last vaccination of broiler breeders, resulting in a duration of passive immunity in broilers of at least 14 days after hatching.