Recovering blackbird

Hi everybody was driving home on Friday noticed a wing flapping in a road gutter stopped & a blackbird was lying with its other wing & head down the grid

Retrieved it thinking it would fly away but to no avail all it did was roll around took it home as it was cold & soaking thought it would die during the night but at least he would be cosy

To my amazement he was still with us next morning fast forward 2 days hes now recovered his balance his neck is ok now & he/she is eating &drinking in an old dog cage of ours.its lost most of its tail feathers but seems ok ,I'm going to see if it will fly tonight in the house 

My question is if he takes flight do I let it go in the garden as we're rural or should I return it to the location I found it about 1 mile away from our house 

Any feedback & advice would be much appreciated 

Thankyou in advance Paul