Hi Sarah,
Is your IRN banded? If so perhaps you can trace her back to the original breeder and ask about his/her genetics.
If unbanded however, you can either use feathers or have someone help you extract blood from it through the toenails. Use a towel if you must to cushion her and also to protect yours and your helper's fingers as your IRN will go ballistic during the entire process. Clip toenails a little at a time until a small amount of blood oozes out. Here's a website of the outfit I use for DNA testing.
http://www.zoogen.biz/contact.html
There's a more detailed instruction there on how to extract blood. The blood sample is actually just smeared on the DNA-sexing request paperwork.