My hens have not been wormed since 'chickdom' , about 10 mo ago. Since we are having cooler temps, they have slacked off on egg laying. Should I worm when I do not see any evidence of them having worms? ( 7 birds free range completely on 6 acres) Should I worm with Wazine? If so, how long off the eggs? How many days on the worming? The package directions do not say.