We use a scheme like this:
1801, 1802, etc... 18 is the year born, 01, 02, 03, etc. Is order of birth. Tags are a different color for each year. Right ear: girls and left ear: boys
For catching our sheep, we use fencing that is like netting (fromPremier1) and slowly make it smaller, getting them into a corner. Then just grab them.
I would suggest getting Soay sheep. They take down coyotes (I've seen them do it), they shed their wool (good for using), are born with short tails so no docking, and eradicate poison ivy, poison oak, or anything in reach. Small, easy to handle, and cute as a button.
I have British Soay sheep, not goats, but hey, I love the horns. Yes, I've been rammed, knocked down, had to free them from fences, etc. Soay ewes and rams both have horns, but occasionally can also be polled. Very similar to goats. I cant tell you how many people have asked me about my "goats" ...