Black bird fledgling

  1. We have 2 blackbird fledglings in our garden both being fed by mother. One is now flying but the other is quite weak, over the last couple of days it has been moving around the garden but today it has sat under the garden table and not moved, its still alive and the mother is feeding it but on inspection (from a suitable distance) i can see its back leg sticking out at an angle and im not sure if its wing could be injured? Ive noticed that there are alot of blue bottles sitting on it aswell!  Any advice?