We used to give ours iodine boluses which last six months I think. You preferably need a crush to administer really. We don't give them any more because we haven't had any more problems.
Talking of iodine our latest addition who finally arrived on Tuesday decided to kick the bottle of iodine out of my hand when I was sorting out his naval, I spent the rest of the day looking like the chap off the tango advert!
