I would like to point out that there are withdrawal periods for most of the products used for deworming chickens including wazine. These products are also not labeled or studied for use in laying hens. My point is that an every 30 day worming regimen for livestock such as poultry is probably not a great idea as this is not recommend in the normal usage of these products. Several take more than 30 days for withdrawal. A once every 30 day regimen is recommended for dogs and cats, but these are not livestock to be eaten.
I dont have anything against treating with a wormer, but an off lable use every 30 days seems excessive. Probably fine for show chickens or gamefowl, but I would not suggest that to people that intend to eat the eggs or the meat.