What information do you want to keep? Why are you tagging them? Are you trying to identify different ones or something more complex. Your system needs to be based on what you are trying to do. if you don't have a reason to tag them you don't need to. It does not help the chicken, the information is for you.
I use a certain color or combination of colors on the left leg to indicate which year they were hatched. One year I used a combination of red and purple, the next year yellow, and the next green. Contrasting colors that really stand out from each other.
On the right leg I use different colors or combinations of colors to identify different birds that look alike. On red birds I might use yellow, red and green together, purple and yellow together, green, blue, just any combination that pops in my head but are somewhat contrasting. I might use the same combinations or colors on black birds (or something totally different) since I can tell the difference in a red bird and a black. I might use a yellow on the right leg of two red birds if their hatch year is different.
If you have two colors, say yellow and green, you can put a single yellow, a single green, and a combo yellow/green for three variations. If you add red, you can get single yellow, green, and red plus the combos yellow/green, yellow/red, and green/red for six identificcations. If you then add blue the number of possible markings go way up.
If you want to keep track of which hatch the chicks cam from, use a certain color for that on whichever leg you want. If you want to keep track of which rooster is the daddy or hen is the mother keep track of that. The system needs to reflect the information you want. I'm sure LG and Aart have different systems than I have and their colors or legs mean things than my choices.
