The front hub of the Birdy is 100mm wide so its standard width.

But the Birdy disc has his disc placed on the right side of the bike at a distance from the dropout which is similar to the distance from the dropout of a rear disc while the usual front disc is closer to the left dropout.

So, its not possible to use a reversed standard disc front hub on a Birdy disc, it requires a specific hub.

The rim brake Birdy use standard front hubs.