Comparison of the moulting pattern of the birds in the Netherlands and Germany confirmed that it is the same bird.
Bearded vultures can easily survive without food for a week or even longer. In its usual home range the big scavenger find their food above the tree line from wild ungulates. Getting food in the countries the young bird is currently flying might be a bit more difficult.
Lets hope the young bird finds its way back to where it originates!