i have some chickens that are going ot be shown in a few weeks and i need to bathe them has any one done it and if so whats the best way?

I've never bathed a chicken. There are dry and wet baths. Dry baths using something like corn starch to soak up oils. Wet baths can chill a bird if the air temperature is too low. I'm not sure what those who show their birds do if they need to be cleaned.