I've yet to go to a show. (they're so far away. . .
) But I know some good things to change with food are higher protein, adding flax and sunflower a little more in their diet for a better, healthier sheen to the plumage, and cut back a little on commercial layer feed. There's a lot of drab things in there like wheat, soy, and corn. (most of the time that's all that is in there, really) These things can actually keep a bird back from appearing and behaving healthier.
One word of caution is do not change the feed too much while getting the bird ready to show, as they might go into a molt because of the feed change. If you feed a good balanced ration there is no need to change feed before a show.
4 months ago I put my show birds on mazuri game bird breeder kibbles. I have seen a big difference in the handle of the silkie feathers and on the sheen of the regular birds
this is my OEGB
One that I've been told to do is to put your Show bird in a cage and a couple a times a day take him/her out. Get them use to being handled.
You can train them to pose in a cage with treats. Get other people to reward the bird for posing. They call it cage training.
Don't wash your birds with soap, just rinse them off about 7 to 10 days before the show. Then after being rinsed off from dirt spray mist in solution Glycerin with water. Glycerin is a vegatable base oil that they will preen them selves with to get the high sheen.
There are other more trait detailed things you can do to get the bird looking great. Great topic for ALL of to read and I thank you for posting it!