I get mine from cutler supply. You can get an assorted colors from them, but NOT assorted sizes. Here is the deal though, you can't buy one size. I bought 4 different sizes so I can change sizes as they grow. I like the color springs the best. I have some numbered bandettes but only for my bigger birds. I use the color springs when they are young. I bought 4, 6, 8, 10 color springs and change up every 3 weeks.
They peck at it themselves at first, but then forget or get use to it. Size 4 only lasts from day 1 to 3 weeks. I scratched a light brahmas foot taking one off today, gotta be careful.