Go over your pastures to make sure poisonous plants are not in the pastures endangering your herd. See link of poisonous plants as a guide. Use organic materials to remove unwanted vegetation. Make that the Alpacas are not exposed to excessive vegetable matter. Keep your pastures clean of poop piles will help immensely with parasite issues. Keeping your pastures and yard areas mowed so that grasses and weeds do not have a chance to set seed. Not only will this keep your forage source growing over a longer period of time, but will prevent Alpacas from being exposed to seed heads that can get caught in their eyes. Tall grass is not good for young crias since the seeds will stick to the eye and cause issues. Keep your pasture at approx 3" high is generally a good rule to follow.