Baby Canary has a yellow transparent bump on it's neck!?

I have three baby canaries, another one hatching any time now. Two of the baby canaries look healthy, everything looks normal but then the third one has a yellowish bump on it's neck. You can see through it. All I see is white dots or something along that in the bump. I don't know if this is normal as this is the first time I've had canaries. Help? Thank you.