Can anyone identify the breed of these ducklings?

[Emmasducks]

I was recently given five ducklings from a school, they were unable to tell me the breed.
3 have orange beaks while 2 have pink, so I was wondering are they all the same breed or do I have two different types here?
They all hatched together in an incubator. - they are just over 4 weeks old.
They are already pretty large, so I was thinking that maybe they are pekin or Aylesbury duck?
Any help would be appreciated.

 

[FoodFreedomNow]

My guesses: those with orange bills may be Pekins and the ones with pink bills may be Hybrid White Layers. Cute group!