I guess the preparation can be as serious as you like..
Firstly read the standards to ensure that your birds are at least very close to the shape/colour/size/skin and leg colour required
About 8 weeks before the show go over the birds and look for bad feathers, on a Silkie they wont be as obvious as on the Wyandotte, look for broken feathers and badly marked feathers (if the dotte is a laced/barred/partridge one)grasp these at the base and quickly pull them out, only do this with the worst and smallest and never try to remove feathers from the wings!
Add a little cod liver oil (sold in the UK for horses not sure about Canada though) to the feed that will add some shine to the feathers, lots of greens (grass is obviously cheapest) will be hugely beneficial too
Keep the birds shaded, blues and buffs especially will fade in the sun
Whether you separate out the birds is up to you, they certainly stay neater if penned individually but I always think they must be pretty miserable alone so pen mine in twos and threes and never with a cockerel during show season (as they will wreck the female's feathers) Show cockerels really have to live alone unless they have been bought up together
If you let the birds continue to run with the rest thats no problem if you are showing for fun or at a low level
The Wyandotte needs to have yellow legs so if they arent a good yellow then some extra maize will help, this wont do the Silkie any harm as long as its not white! (too much maize can tint a white bird)
Embark on a weekly check for mites/lice and preventative treatment
in the weeks before the show get the birds used to being handled and spending some time in a show pen (improvise with a small dog crate or homemade wooden box with mesh front) feed it some treats while its in the cage, this training means that the show cage wont come as a surprise on the day (its obvious which birds are used to them and which arent) and also makes the bird very happy to see people, judges like it when the bird shows interest and alertness rather than stress or indifference
Also start to clean the legs of the birds every week or so, this helps with getting them used to being handled and also means that the legs arent really dirty when the time comes to bathe the bird nearer the show. a toothpick very gently run under the edge of the scales will dislodge any dirt build up, keep working on the legs and when bath day somes they will only need a clean up with an old toothbrush hopefully
Bathe the bird about a week before the show, clean the legs first in separate water then bathe the bird in warm chicken chest height water to which some shampoo has been added (horse shampoo is excellent, dog or baby shampoo are both ok too) dont apply the shampoo directly to the bird, gently work the warm water amongst the feathers, dont rub against the feathers though, run your hands under the wings and spread the wings out in the water to get them really wet
Rinse in another bowl of clean warm water, a final rinse in clean water to which a drop of vinegar has been added really makes the feathers shine
Dry the bird gently in a towel (you can use a little horse coat shine on the Wyandotte if you wish) let the Wyandotte dry naturally indoors in a box or in a warm garage/shed overnight, the Silkie will benefit from the use of a hairdryer to make it all puffy
Keep the birds clean till show day, this normally means they get penned on clean bedding in a small run
On show day check that the legs are clean and use a little baby oil on the legs and comb to make them shine (be careful not to get it on any feathers so the Silkie could be tricky!)
on arrival at the show find your pens and place the birds gently in them running your hands over them to take stray feathers then let them settle and go for a coffee!
You needent do all of these things, it really depends on what standard you are aiming for