Mallard Band Size

[texan68]

Not sure if this is the correct section for this but I’m sure someone here knows. I have a small flock of domestic “wild” flying mallards on the homestead. I’m trying to band them for ID purposes but have hit a bump. I ordered size 14, which is 11.13 mm, the equivalent to the size 7A federal band size for mallards. I received them yesterday and the bands are far too small. They won’t come close to closing without damaging the leg. These birds are only 4 weeks old so I’m having a hard time believing what I’m seeing. The legs do not appear to be all that large compared to mallards I shoot on the regular. Has anyone had this issue before? If so, what size did you go up to?