Broiler litter was sampled from brood and non-brood areas of a production unit after consecutive 6 week growing periods; litter present after each of the first five periods was placed in dacron bags, embedded in litter located in similar areas of the production unit and removed after subsequent growing periods to determine changes in chemical constituents that relate to feeding value for ruminants. Litter harvested before the fourth 6 week broiler growing period yielded organic matter concentration lower for brood versus non-brood litter: Organic matter concentration in non-brood litter stabilized after two growing periods, whereas organic matter concentration in brood litter increased linearly with increasing number of growing periods. For obtaining non-brood litter comparable with brood litter il I nitrogen concentration, harvest after the fourth growing period was warranted There was little or no effect of the number of broiler growing periods on neutral detergent fiber concentration in brood litter However for a neutral detergent fiber level in non-brood litter similar to that in brood litter harvest after the third growing period was necessary. Neutral detergent soluble organic matter concentration increased to approximately 30-35% with harvest after at least three consecutive growing periods; the magnitude of change in non-brood litter neutral detergent soluble organic matter concentration was, relatively, greater than that for brood litter because of a lower initial level.