I know this is old...
He is prime age for coccidia which are NOT worms (protozoans) and dewormers will NOT work for coccidia. Get a fecal to a vet.
Coccidia is species specific.
What is the brand and Calcium/Phosphorus ratio of your feed? Off balance ratios lead to urinary calculi. If...
Urinary Calculi is from almost always from improper Ca/P ratio. When you are feeding bucks/wethers you need to keep in mind what the ratio is in the feed you are giving, hay, minerals, etc. It should be In between 2:1-4:1. Often some hay such as alfalfa or perrenial peanut should be given to...