It depends on why you are using it- if you just feel you want to give them a tonic I expect it will be good for them as its a natural antibiotic, though it won't kill worms, for that you need Flubenvet. There are quite a few poultry tonics available with a wider spectrum of nutrients and minerals.
I use 2 cloves, crushed and then popped whole into a large drinker. I also add Apple cider vinegar at 20ml per litre.
This time of year twice a week they have a couple of tablespoons of cod liver oil mixed into feed.