It is quite confusing at first but once you get the hang of it, it's invaluable (to me anyway)
I know some people will say "why all that?" It works for me, that's all I can say.
Some just write a # on their belly. I don't like that because for one, you have to pick them up to see it & it doesn't show up in the pic. I think it's a lot less likely to mix up the pics etc. when trying to identify them this way.
Some people put paint on their heads too???? I don't care for that either. They are covering the "third eye". I don't know if it could cause any problems but why risk it?
It is a 4 digit system.
This is the color code
Red = 1
yellow = 2
green = 3
blue = 4
white = 5
black = 6
I.E.
#324M

Okay, the 1st number represents the clutch # so this guy is from clutch #3
the 2nd number represents the top color dot in this case yellow =2
the 3rd number represents the bottom dot, blue = 4
and the M or F are the sex and I put a pink or baby blue mark on their rear leg or on the side of the tail base to indicate that.
Here is another one #312F
Hope it helps
