There was a study that came out in the last few years where they had found that peppermint had improved egg production. So far I have not had the time to cultivate THAT much peppermint to be able to feed it to the hens and see how it does.
I have been thrilled with putting garlic in the water this year though. Normally when it is hot, the hanging nipple water buckets get black mold/mildew in them really bad unless the water is completely dumped and refilled daily. But this year I started putting a clove of garlic in the water - talk about keeping the mold/mildew at bay. I don't have to dump tons of water every day anymore. I've also put in oregano oil and garlic to see what happens - talk about clean water! Like well maintained pool water, nice and clear. The hubby teases me that I am just pre-marinating the birds. But even he has been impressed with how clean the water stays and not having to replace water every day and can just do some topping off. It's rare for us to have ill birds so I originally just added the garlic for the health benefits thinking it couldn't hurt anything, but the clean water from the garlic's influence has been worth a fortune in not wasting so much water and in time needed to clean out buckets.
There is much to be said for going back to basics and *old wives' tales* when caring for people, animals, and their environment.