If you can get a decorticator and a grinding mill, you would be set. You may or may not need to wash the meal, depending on how palatable it was to the chickens.
Cornell University’s Dept of Animal Science states: “Generally, tannins induce a negative response when consumed. These effects can be instantaneous like astringency or a bitter or unpleasant taste or can have a delayed response related to antinutritional/toxic effects … Tannins negatively affect an animal’s feed intake, feed digestibility, and efficiency of production. These effects vary depending on the content and type of tannin ingested and on the animal’s tolerance, which in turn is dependent on characteristics such as type of digestive tract, feeding behavior, body size, and detoxification mechanisms.”
Their studies have shown the following information worth noting:
Animals fed diets with a level of tannins under 5% experience
depressed growth rates,
low protein utilization,
damage to the mucosal lining of the digestive tract,
alteration in the excretion of certain cations, and
increased excretion of proteins and essential amino acids.
In poultry, small quantities of tannins in the diet cause adverse effects
levels from 0.5 to 2.0% can cause depression in growth and egg production,
levels from 3 to 7% can cause death.