Let f be a transcendental entire function of order less than 1/2. We i
ntroduce the method of ''self-sustaining spread'' to study the compone
nts of the set of normality of such a function. We give a new proof of
the fact that any preperiodic or periodic component of the set of nor
mality of f is bounded. We obtain the same conclusion for a wandering
domain if the growth rate of f is never too small.