Your welcome
I've only used them on budgies, I was going to start marking the eggs so I knew exactly which one hatched So I'd get the correct hatch date
and i've used them when I fostered eggs the smearing part wasn't bad on a fostered egg, because I just needed to know if it was a fostered egg or their egg that hatched so if it smeared that was ok (i'd use a different color for a fostered egg,than what I used on the pairs eggs) but when I needed to know the numbers it was a pain, because they'd all be gone
Could of been i just didn't do it right as well lol even though I did it right where a website said to but that doesn't mean I did it right lol