I just applied four different colors of food dye into four different hen's vents. Does anyone else do this to help figure out who is laying which egg? I did basic green, red, blue and yellow. I figure that I could get those neon colors and get pink and purple too. I did this once before and it worked. Just wondering if its safe for the hen. How often would I have to do this? Every week? Is there a better way? I don't have trap nests but I have thought about it.