Viscosity is the moisture-binding capacity of the raw materials. With high viscosity, the food in the digestive tract becomes ‘viscous’, thus ensuring a longer digestion time. Enzymes are less able to break down the nutrients at a very high viscosity. The gizzard contracts more often through the stimulation of coarse particles and crude fiber. The feed particles move on to the small intestine once they are reduced further.

Food stays longer in the stomach if the particles are coarser. The particles affect the functioning of the gizzard. Parts like ground grains provide a positive stimulation of the gizzard. By adjusting the particle size, particle shape, crude fiber, and viscosity, the speed of digestion can be regulated.