We have 6 adult Sebastopol geese, 4 females and 2 males. I have put colored zip ties on their legs to help me identify them. We just built two seperate coops for them for mating season and I will seperate 2girls with one boy and keep the same trio together. The problem is with their feathers it’s very hard to see the zip ties on their legs. I have tried using food coloring but it comes off very quickly. Is there something I can put on them that will last? Squirting something on them would be easiest as they get pretty upset when I pick them up. Also this will help if I have to have someone else put them in if I am not here. Thanks