From the lighting and background it's hard to tell but I think I see curved tail feathers and pointy wing feathers.
I would think at 6 months it would be obvious though. I don't see any spurs either.
Agree. Looks a bit younger. Additionally, his breeding isn't all that good, so we're seeing mottled barring and a darker overall look. I'd say cockerel. Not standard bred Barred Rock. With two barring genes, a BR cockerel of that age should look like this.
I am FAR from an expert- my guess is a Roo. My BR was very round and hen like at 5 months, no curved tail. I was looking for a good pic of her from that age-
Her head is blurry- but you can see her tail feathers ok- I think.
The lack of the double barring gene, required for a BR male, makes his over all look dark. Plus, the barring is blotchy. This likely indicates that he is a cross. The tell tale sign is the gold/red/brown leakage in the wing. Unless that is merely a photographic anomaly, those red/brown feather indicated leakage of the gold/red of the other portion of his genetic makeup.
If this bird had a red comb and red wattles at 7 weeks of age? It is indeed a male. Males show that characteristic very early. Pullet don't normally show any comb or wattles development until they are much older, around 14 weeks.