Recently while I was doing some volunteer work with the farm animals a person asked my opinion about an article they had seen using oregano essential oil with chickens. I am choosing to not share the link to the article because I do not want people to think I promote the authors suggestions. Unfortunately the article didn’t state which type of Oregano they utilized I have to assume it was Oregano vulgare.
Oregano essential oil is generally high in carvacrol and thymol. These chemical constituents lend to the possible therapeutic uses with viral infections, bacterial infections and helping with congestion. The author references investigating essential oils in the prevention of Avian flu. I did an extensive search through PubMed, one search and couldn’t find any research on Avian flu and oregano oil. Due to the therapeutic benefits with viral and bacterial infections this oil may help with prevention, as long as it was used safely and highly diluted.
For human use the oil has a recommended maximum dermal use of 1.1% and several cautions against oral use (pg. 375 & 376 Tisserand & Young 2014). Knowing these precautions I would never suggest use of this oil with chickens, simply because they are small birds with completely different systems. The only way I would use it would be during cleaning of their coop after illness and when all the chickens are removed for a period of time.
To ensure the health of your flock rather than turning to essential oils consider using the actual plant. Adding a variety of herbs to a nesting box can help deter pests, add a healthy snack and create a fresher environment. The fresh herbs will also provide vitamins and minerals which are not available from an essential oil. If you do use fresh herbs these will have to be changed frequently to avoid mold developing, if you are in a humid area consider dried herbs.