The one that goes in the shed... shut the door and catch it. Put it in a smallish wire bird or wire rabbit cage.
Put this outside on the ground where the other pigeon can see it and where it has been walking before.
Put a feeder next to the on in the cage with pigeon mix.
Over the feeder put a large wire basket, or cage with no bottom, or even a large box. Prop it up with a stick attacked to a string.
Stand well back, hide, whatever and wait till the other pigeon flies down and starts to eat the food. He will be attracted to the food and the other pigeon. Then simply pull the string and the cage will fall over him, trapping him.
be careful getting it out not to loose it. You could have a small door in the larger box / cage to put you hand in to get it, rather than having to lift up the bottom of the box.
Put the pigeons both back in the coop and let them settle down. T he next day start training them to come for feed 1 X a day. After they fill up, take the feed out. Never leave feed in there all the time as they won't be hungry to come back.
Once they are good at coming to the feeder when you call them, and are not scared of you, then you can start to let them out again, calling them back in etc.
Once they are being good, you can divide their feed ration up into 2 smaller servings, morning and late afternoon.
Good luck.
the other one is great joe comes and hues from the shed and I feel I can trust it now x
