Barred rock 7 days old male or female from looking at the beak

[Annie08009]

Male or female from looking at the beak?

 

[nuthatched]

Can you get clear pictures without the red light?
How do you expect to tell the difference by their beaks?

 

[NatJ]

How do you expect to tell the difference by their beaks?

Probably because males have two barring genes and females have just one. Having two barring genes means males are lighter in many places: larger spot on top of the head, lighter feet, more white in the feathers when they grow, and I would not be surprised if they have lighter beaks too.

Personally, I would not try to sex them by one single trait. Looking at several things is more likely to be accurate (because a chick with a confusing head spot might be have obvious feet, and so forth.)

Can you get clear pictures without the red light?

Yes, photos with natural lighting are much better for seeing colors correctly!

Edit to add:
I found an article about sexing Barred Rock chicks by color, and it says the beaks are less useful than other areas. This is from 1939, when people were first learning that sexing them by color was possible at all. I can't seem to make a link to the .pdf, but here is a copy of the header information in case anyone wants to try to find it with a search engine:

POULTRY SCIENCE
July, 1939, Vol. XVIII, No. 4
Sex Identification of Barred Plymouth
Rock Baby Chicks by Down, Shank,
and Beak Characteristics
JOSEPH P. QUINN AND CHARLES W. KNOX
Bureau of Animal Industry, U. S. Department of Agriculture, Washington, DC