Not all birds can be wing-sexed - it is not accurate with most breeds. What breed are they? I think they also may be past the age where it can be done even on the breeds where wing-sexing is possible, but I am definitely not an expert. But breed will be important to know :)
The wing test is rarely accurate at that age unless they're sex-linked by color or something. We'll give it a shot anyway if you want to post pictures though :D