Does size difference in same age chicks mean different sexes????

[Dwells]

Yesterday I purchase two Speckled Sussex chicks. I noticed today that is a size difference in the two. The difference is not extreme but is noticeable. I am thinking that due to my luck in raising new chicks and the roo to hen drations is 50/50 I may be looking to hard.
I am not allowed to have roosters and had to re-home three gorgeous birds because because the breeder can not seem to tell the difference. I would really hate to have to re-home another one. These two are very cute and the wife and kids have already fell in love with them. I just wanted to see if there is anyone else who has experienced size differences ending in roo and hens. I estimate the age to be around 3 weeks. The place where I purchased them did not seem to know the exact age.

 

[ChickenCanoe]

That's usually the case but I would wait longer it usually takes a few weeks to tell by size and I've had runt cockerels too.

 

[Wyandottes7]

That's usually the case but I would wait longer it usually takes a few weeks to tell by size and I've had runt cockerels too.

X2.

 

[BantamLover21]

X2.

x3