If it hasn't got a ring it may be just a ferral pigeon, if you give it some food and most importantly water it will prob clear off in a couple of days.
If they are ready to train Bob then Do'nt worry about them roaming, i've had years when mine have stayed in view and others where they have gone off for hours but the result has always been the same.
Splint it as said and suspend the bird in and old sock etc for 10 days to alow it to set and it'll be fine.
When you splint it if there is any open wound put some wound powder on it to help prevent infection and try to set the leg as near to original position as possible.
Is the ring damaged?
they will soon eat from your hand/ food tin when they are hungry, once they have the confidence to take food from you they will keep doing it. All about building confidence.
make sure your photo's are smaller than 1mb, click on more post options below reply box, click browse, find pic and double click it, click on download/attach and post it!
thank you all, the birds offered and in the pipeline are going to be second to none.
It just goes to show how somethings effect fanciers and the generosity they continue to show is overwhelming.