Conventional induced molting usually involves removing
feed, water, or both from the hens and reducing the
photoperiod to that of natural day length or less. Hens
are then fasted for a length of time sufficient to affect
complete involution of the reproductive tract. If water
restriction is involved, it is usually removed at the beginning
of fasting and may be continued for up to 3 d.
Molting is said to be induced during this time, as egg
production ceases and the reproductive tract rapidly involutes.
The period during fasting and following refeeding
when egg production is essentially at zero is referred
to as the rest period. During the rest period following
fasting, various molting, developer, or resting rations are
often fed as a part of some molting programs. With the
onset of renewed egg production, a layer ration is returned to the flock, and a supplemental lighting program
is initiated. Egg production then rapidly increases to a
level above that immediately preceding the induced molt.
By this time rejuvenation has occurred. The length of
molting, defined as the time from initiation of fasting until
50% egg production, varies with the particular molting
technique and conditions. Induced molts generally range
from 5 to 9 wk in length