Marking ducklings to identify them.

[Stoney Meadow Maple]

I am ordering ducklings that I will be brooding with ducklings that should be hatching all at about the same time. I want to identify the ones I plan to keep vs the ones I plan to get rid of, what’s the preferred method? Paint on the bill? Leg bands? If so where do I get them? I bought some a while back that had something like a key ring around their legs, it was plastic, but it got very tight and was hard to remove.
TIA

 

[judyc]

Colored wire ties. But you have to keep an eye on them since ducklings grow so fast. Wire ties are cheap enough that you can cut them off and replace them.