black wyandotte

I purchased this bird at 5 weeks old supposed to be a pullet but looking at her/him he is big. I feel like it might be a roo but I'm in denial so I thought I would get other's feedback. Also wondering if it might not be a pure breed. Thoughts? He or she is 4 months ish...

Hello. I moved to the country a year and a half ago, and finally have time this summer for a garden and some chickens (not together, I've heard). Last week, I bought eight 2-to-3-week-old chicks: 3 Black Wyandottes, 2 Ameraucanas, 3 Blue Laced Red Wyandottes. These are living in my...