Small Magpie unable to fly

Hello,  We have a small magpie who is unable to fly in our back garden.  It looks well and is hopping about and It’s parents are are feeding it but there is also a turf war between the Magpies and two Crows and it’s quite uncomfortable to watch.  We also have a cat but thankfully, at the moment he is just watching it all.   We have only just found the small Magpie but the battle with the Crows has been ongoing for a couple of days now. 

What can we do to help?