"
A study conducted by
The Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra found that spent coffee grounds contained 3.59 to 8.09 milligrams of caffeine per gram of used coffee grounds." <---- Directly from the link you provided.
Here is information I have been providing in several responses throughout this thread:
I addressed all Q&As collectively from this thread here:
https://humble-hills-farm.com/2020/07/24/using-coffee-grounds-as-chicken-coop-bedding/
In summary, the used grounds are considered decaffeinated (less than 9mg of caffeine for a human serving size). There has been no research to suggest caffeine is toxic or not toxic to poultry as they are to mammals.
I found only one official research article which even included coffee as feed for chickens.
The Inclusion of Coffee in Commercial Layer Diets, published in 2011, included 125 laying hens which were split into groups: a control, one fed 1.2% of their diet with caffeinated coffee (roughly 9 mg of caffeine per bird, considered a “moderate” amount), and the other fed a diet with 1.2% decaffeinated coffee. The study lasted between 21 and 35 weeks. The authors were assessing the affects coffee might have on the feed intake, egg production, and egg quality of commercial laying hens. What they found was there was no significant difference in feed intake, egg production, egg weight, egg mass, or feed conversion rate; however, egg shells were slightly thinner. They conclude by saying
, “No scientific articles on feeding coffee to poultry were found, and therefore, further studies using coffee dregs, because it is a cheap byproduct and with economic potential, are recommended.” The unspoken conclusion here would be coffee does not appear toxic to chickens when consumed continuously in moderate amounts for a period of five to six months.
In reality, some bedding that we commonly use are also possibly toxic (I’m looking at you,
pine shavings and
straw), and yet farmers, backyard chicken keepers, and homesteaders continue to use them. I have been using coffee grounds in my coop for five months now to no ill-effects and will continue to use them. My chickens do not express any interest in eating the grounds, or if they have they have not had any objective health issues. Every chicken is different so my experiences may not align with yours. I think the economic potential of coffee dregs lies in it’s use as bedding, not feed.
