A bird which has gone without water for a while is sometimes a bit less than itself. It may be so exhausted, it doesn't even realize that water is in front of it, especially if the water container you use is different from what it is familiar with. A trick I've often used is to trickle a few drops of water from on high into the container to make a splashing sound. When they hear that, most birds will invariably head to drink. If a bird looks really exhausted, Gatorade or other proprietary sports drink may be added to the water.
Pigeons are grain eaters.
While park pigeons will eat bread, most domestic birds have been raised on a multi-grain mixture and have never seen a slice of it. In fact, they would likely ignore it as possible food. Instead of bread, you might try feeding them something else from around the house. Water should also be provided since pigeons normally drink immediately after eating. Any container that a dog or cat can't get into will be fine.