A major impact on gut health through microbial activity is also caused by an often overlooked factor. Where digestibility is used as a tool for calculating available nutrients to the animal, the other part of the ingredient, the part that does not get digested will end up as nutrients for bacteria in the hind gut. In older animals, this can be controlled by the gut itself. But in a newly weaned piglet or newly hatched chick the microflora is still struggling to find a balance.