When carefully separating eggs, what to do with the chalazae?
The function of the chord, that is attached to the yolk, is to hold the yolk into place. To have the most uniform baking possible, you remove the chord. However, I never do. I keep it in with the rest of the whites and I've never had any problems with the finished products.

So you can:


toss it
keep it with the yolk (a little bit of whites with the yolk is not bad, the other way around is)
keep it with the whites since it does not contain fat, it will not stop the whites from being whipped


It's up to you.