Newbie help with gender please :)

[gemgem84]

Hi, I'm pretty new to all this.
I have 3 chicks Buff Sussex (7wks), wellsummer hen (12wks) and grey legbar hen (9wks). I also have a 7wk runner duck (male).
I was wondering if you could help me sex my Buff Sussex, I'm thinking Roo but unsure. Picture attached.
Also am I correct in thinking I should worm them soon as they are now outside. What is the best to use as the duck is in with them?
Thank you

 

[ramirezframing]

Your LIGHT sussex looks like a pullet for the moment.

 

[Basskids08]

Wouldn't that be a light Sussex pullet? I don't see buff color anywhere for it to be a buff. Are the rest this color too? If so then they are all light Sussex. You can worm them now!

 

[DesertChickens1]

Judging by the size and the color of its comb I would say a pullet

 

[gemgem84]

Thank you, sorry about the error it was sold as a buff but has changed colour so is a light sussex

 

[BantamLover21]

Light Sussex pullet.