Last year I started using colored lamb ear tags. With color coding, I was able to keep track of sire, and that a lamb was a single, twin or triplet. From afar, I was able to compare Burgess' lambs (blue sire tag) and Duncan's (purple sire tag). Early on I did not worry if a lamb with a lime ear tag was a bit small, after all it was a triplet.
In the past,ewes and their lambs were marked with one (single), two (twin) or three (triplet) lines to quantify the type of birth. This year I will paint the dam's ear tag number to their lambs' backs to aid in quick, from-across-the-barn assessments. This will be helpful early on when lambs can get separated from their ewes and later in the spring when they are first out on pasture.