First of all we should know that all goats have worms. The problem is when the worm load becomes too large and it can harm the goat.
Goats are closely related to deer and they are browsers. This means they prefer leaves to grass. They naturally eat from the top to the bottom. This is there way of protecting them from worms since worms are more often found in the grass than in the trees.
Breeders often ask how often they should worm their goats. Well this depends on a lot of factors. Wet conditions, the amount of browse they have, and overcrowding can all affect the worm load.
The best way to kknow if your goat needs to be wormed is by doing a fecal test. Many breeders will do their own if they have a microscope. A microscope is a great additon to your supplies. If you are unable to do a fecal, your local vet will be able to. If this is not possible then I reccommend you go by the FAMACHA chart. You should be able to find one on-line . They also have classes to learn how to read the chart. You should only worm your goats on an as needed basis to avoid a resistance to treatments.
There are several treatments available. Some breeders use natural products while others use chemicals. I have found that the chemical treatments work well for my farm. I would also suggest that you DO NOT rotate your wormers. Find one that works until it just wont work any more. Some breeders also use a womer that is placed into their daily food. The problem I find with this method is that there is no way to know which goats got enough wormer and which ones didn't.I would not reccommend this method for that reason.
Some signs you may notice if your goat becomes wormy could be:
clumply stools, off their feed, pale gums, rough appearing hair coat, lower milk production, a chronic cough (may indicate lung worms), or a swollen jaw.