I am not a judge, and unless it's an exceptional bird, even judges won't judge from a picture. If it's a 4-H project, the kids will be asked to hold their birds properly to show them. If you're showing as an adult, the judges will open the cage, take out the bird, examine it, then return it to the cage. The do this with each bird.
Bathing: Get 3 totes, a plastic cup, a small toothbrush, and enough large towels to dry, and wrap them in. Put enough warmish water into each, that the chicken can sit/lay down without it totally covering their back. To the first, add a little Dawn Blue Dishwashing liquid, like for washing dishes. To the second, add about 1/2 a tsp. of vinegar. The third will be plain water. When you first put the bird in the water, it will probably go a bit berserk, but they quickly settle down, and sit down. They actually LIKE their spa time. Let the bird soak in the warmish soapy water, but don't get any soap in the eyes. Feel around it's vent, so that any pooh softens, and comes off. Use the cup to pour a little water on the back, under the wings, and up the neck, without getting it into the bird's eyes. Just before you go to put them into the vinegar rinse, use the soft toothbrush to clean any debris from their feet, their toenails, and leg scales.
Next, put it into the vinegar rinse, using the cup as you did before. It doesn't have to stay in long. Finish up by putting the bird into the plain water for the final rinse. Make sure it's rinsed well. Now, lift the bird onto a towel, set the bird down on the towel, and wrap the towel around it, sort of like a burrito. By now, the bird should be calm, and happily stay wrapped in the towel. Get new warm soapy water, and proceed to the next bird. Rinse, repeat. While they are calm, and relaxed in their towel, trim toenails, and spurs as needed.
The next step depends on how long it will be before you show them. If you're cleaning them a couple days, or more before showing, skip this step for now, and do it when you get to the show. If you're going to show them the next day, take a little Vaseline, and rub it into their comb, on their beak, on their legs, and on their toenails/spurs. Take the time to let the Vaseline warm in you hand, and make it a very thin layer, taking time to rub it in gently. You don't want it too greasy, or dirt sticking to it. You only want the little extra sheen, and suppleness that it lends.
Things to take to the show. Bottled water, soft toothbrush, lots of wipes, Vaseline, plastic cup.