I also have lots of livestock and also do them twice a year.
http://www.fresheggsdaily.com/2014/02/common-herbs-and-their-health-benefits.html?m=1
This is a great page about what herbs benefit your flock.
I let people come see my flock with appointments, I also know Terry Jones (903-388-4440) lets people look at his program, but he mostly breeds waterfowl.
I deworm with Wazine twice a year during my hens molt so it doesn't effect their egg laying. You shouldn't deworm chickens under 12 weeks of age, so I would recommend doing it once they start their first adult molt. Are you ok with chemicals or do you want a natural solution? I also do natural...
I use Wazine twice a year, it's a poultry and swine dewormer that you can get at a local feed store. It does have a two week withdrawal period where you cannot eat the eggs which is a bummer but understandable.
I also do natural remedies year round including garlic, wormwood, nasturtium, and...