I got 3 barred rock chicks about 4 weeks ago. I'm fairly certain the other 2 are pullets but not so sure about this one. Slower to feather than the other two make me lean towards cockerel
Do you have any pictures of the others for reference? Because it could really depend on it's growth rate. It somewhat looks like a male, but I would need other pictures to be sure.
-Kyle
The bright white bars suggest a cockerel. Pullets are generally dark and the white bars are more spotty at this age. In a few weeks, only the cockerels will sprout red combs and wattles while the pullets will remain yellowish. It is quite obvious at 5-6 weeks.