The products and supplements from Dr. Rob Marshall were developed to promote a strong natural resistance in your birds, thus preventing the need to constantly medicate the flock to cure illnesses. Once natural resistance is acquired, your birds will have the ability to fight off the harmful effects of most foreign organisms to which they may be exposed. My experience with the Marshall Health Programmes for the past 6 years has shown me that this natural resistance will develop most readily in the chicks produced on the system. Those birds coming onto the Health Programmes as adults will also benefit from the quality of the supplements. These benefits will be demonstrated by an increased noise and activity level, as well as improved feather color and quality after the annual molt. But depending upon the strength of their existing immune system, they may not demonstrate the same immune quality as the chicks that they produce on the Health Programmes.