PoultryTalk.com

Before any show, your birds will proberbly need some sort of bath and brush-up. Here's the easiest way we have found to do this, our birds are large Orpingtons, so big and fluffy!
Always bath your bird a few days before the show so the feathers have time to settle and lie straight and the bird has had chance to have a good preen afterwards, this also allows the natural oils to come back into the feathers.
Where ever you choose to bath the bird, it must be warm and draft free. It's easier if you prepare the room and water first so you're not running round with a soggy wet bird getting cold!
Run three large buckets with warm water, we use the sink for getting them soapy and two large gorilla buckets for rinsing, pour a small amout of shampoo, human or dog shampoo is best, we found horse shampoos to leave the bird greasy, as with baby shampoo,into the water and mix well, fill the second bucket with warm water and a good squirt of conditioner, again, human one. This is optional, but on fluffy birds works wonders! The third bucket needs to be clean clear warm water. It's best if there's two people one to hold the bird, and one to do the scrubbing. Have a couple of old towels at the ready. We have found that most birds quite like a bath, and some even fall asleep! Give a good grip base in the sink, by cutting an old shower/bath mat to fit the bottom, non-slip will prevent the bird feeling unsafe, and feel more relaxed. Hold the bird firmly and lower into the soapy water slowly so as not to frighten them, using a plastic jug, wet the bird down to the skin, add a little more shampoo and lather well working into the skin to remove all the dirt. Be careful not to get water in their ears, or you will have a bird which will shake it's head all through the show and look like it's got something wrong with it! And watch out for the delicate part around the eye avoiding getting soap in them.Give particular attention to around the vent/bottom, working the soap well in.
When you have the bird well scrubbed, lift out half way, and give the leg scales and nails a good scrub with either an old toothbrush, or nailbrush to remove dirt,the warm water will have softened it, and stubborn dirt you can pick out later with a toothpick.
Then lower the bird into the conditioning bucket, and rinse well, finally, the clear water rinse making sure you remove all traces of soap and conditioner, squidge the bird to remove access water, and wrap in a warm towel. Cuddle for a few minutes squidging water from the feathers.
Place the bird on an even surface, but again, non-slip, we use a damp old towel on the worktop. And using a hair dryer, or in our case two hairdryers, gently blowdry the bird, for big fluffies, we give the feathers a good rattle both the wrong way of the feather, then the right way in which the feather lies to smooth them out. Mind the hairdryer doesn't become too hot or burn the bird. When completely dry, underneith and under the wings etc. the bird is then ready to be caged in a warm quiet place. Some folks like to dry their birds in boxes in front of the fire or a radiator, but we have found this to takes too long for the orps as they have so much under fluff, but with smaller less fluffy breeds, you get a smoother finish if left to dry in a box.
This is how we bath our birds, and have found it the easiest way out of the few ways we have tried, if you follow this guide, you may find your own little ways the more you practice. Good luck!
JubesX