Mites

I never really recommend "home remedies" for mites. I generally like to stick to natural methods if they are effective, but with mites this is not the case. I have found no natural or home remedy to be effective in killing mites, and only chemical options have worked in my experience.

Permethrin dust is the typical treatment - it's effective but difficult to apply, requires multiple treatments, and may leave residue in the yolks of the eggs for several weeks post treatment.

WD-40 is one really amazing treatment I've found (yes, really - it kills the mites and lice on contact), but given that these are show fowl, you may not want to use it, as it can cause dry skin where applied and will make the feathers oily and sticky for a couple days post application.

One thing you might consider is flea bath shampoo. Since they are show birds I assume they will be bathed prior to the show anyways, and flea baths are great because what doesn't get killed by the shampoo will drown or be washed away anyhow. I've bathed several birds to kill mites/lice and it was very effective.