I use colored numbered leg bands. (Culter Supply, $37 for 100 bands, 1-100) I usually don't band them until they are at least 20 weeks, or big enough that the size 11 band doesn't fall off. Different color for every year. White = 2012 hatch, Blue = 2013 hatch, Orange = 2014 hatch, etc. The bands are re-used if a banded bird gets processed. or sold.
My worry with the zip ties is that sometimes their legs are still growing, and IF put on too tight, they can cause damage. If left somewhat loose, then there isn't a problem, and zip ties work well.
Sometimes the colored bands fall off, but they are usually located soon enough. If not, then I also know who is missing a band and they get re-banded.