I have listed any sellers that I know of on BYC of those brews below :
Sicillian Buttercups :
https://www.backyardchickens.com/t/621051/buy-now-sicillian-buttercup-eggs
https://www.backyardchickens.com/t/895013/10-rare-sicilian-buttercup-hatching-eggs-shipping-additional
Exchequer Leghorns...
I have listed below all of the sellers I know of on BYC that are selling those breeds :
Silkies :
Black, white and paint :
https://www.backyardchickens.com/t/1121018/18-purebred-silkie-hatching-eggs
Chocolate Silkies :
https://www.backyardchickens.com/t/1117185/chocolate-silkie-hatching-eggs...
I have listed all the BBS Silkies that I know of for sale here on BYC below:
Blue, black and paint :
https://www.backyardchickens.com/t/1121018/18-purebred-silkie-hatching-eggs
Blue Black Splash, white, partridge and buff ...
Below I have listed Bantam Wyandotte Sellers Thant I know of here on BYC :
BLRW (not sure if these are bantam or not) :
https://www.backyardchickens.com/t/1105337/blue-laced-red-wyandotte-hatching-eggs
BLRW (not sure if these are bantam or not) ...
I suggest that you ask on the New Hampshire discussion thread to find people near you.
https://www.backyardchickens.com/t/357963/new-hampshire
What kind of Pullet are you looking for?
I recommend that you check out the threads I have linked below, I'm sure you'll find them informative:
https://www.backyardchickens.com/t/821717/how-to-raise-a-rooster
https://www.backyardchickens.com/a/raising-roosters-as-a-part-of-your-backyard-flock...
In order to sex your chicks, you will need to get a photo of each one's comb and head, unfortunately the backwards shot does not suffice. Also, at this age they are probably too young to sex anyway.