Zip ties do not come numbered. You just have to get whatever color you want/can find. We get our spiral bands through various online sources - whoever happens to have the color/size we want in stock for a decent price. Some places only sell packages of them that are one color, other places sell multi-colors in one package, and then you have to see if you want multiple sizes in one package or just one size. We just get whatever we're needing at the time. You get the size rings that fit your chickens. There are a lot of places that have recommended sizes for different breeds - adults. They don't work for us. None of the size charts have our breed, so when we looked at a breed they did have, that is similar sized to our breed (Rocks), and tried the recommendations, the recommended sizes are way too small for our birds. Every chart I've seen recommends something like a size 12 band for a cock and a 10 for a hen - our cocks wear 14s and 16s and the majority of our hens wear 12 and 14s. You can get small rings for chicks, but you just have to size them according to what fits and gives them room to grow but not be too big to fall off. We used to band every chick after about 3 days old - the smaller spiral bands do not flex well and are hard to get apart. They are so difficult to put on without really squeezing the chicks legs, so we only did it after their legs got a little bigger - worried about breaking a newly hatched chick's leg. These days, we don't band until they get older, now that we are accustomed to our breed. Every once in a while we will band a chick to watch them, but we generally just use zip ties in that case. Sometimes it's just too difficult to find the time to change the bands as they grow, so waiting until they are older is easier unless there is a really good reason to band them young.