Welcome to BackYard Chickens charbel!
At this age - It is very hard if not impossible to tell the sex, unless you have sexlinks.
You could try vent sexing, but you
have to know what your doing or you could
seriously injure the chick. Try getting somone who has experience with vent sexing
to help you - if you can. When they are less than 24 hours old, you could feather sex
them. They are born with 'pins' in their wings. Basically the feather shaft, but no feathers.
Because the female usually gets the feathers faster, theres often already a start of the
soft feather coming in on top of the 'pin'. Males only have pins - no feathers starting.
Once again, this has to be done with-in the first 24 hours after hatching, and it's not
a definate way of telling the sex. Once they get old enough, you can usually tell by the
size and color of the comb. Birds with bigger more brightly colored red combs are usually
male, and the birds with smaller paler combs are usually female. What kind of birds do
you have? You can somtimes tell by behavior, but again this is somthing you have to
wait until they get old enough with. Posting pictures would
really help.
~ Scissor