Hard to say for sure, but I'm thinking some of these bigger birds just don't cook up so well. It's possible it just needed more time despite reading 165*. This "gamey" taste you speak of I get every now and then and it's just not very good IMO. Recently I've been trying to get some fresh/never frozen chicken. Even if a chicken is not frozen in the bin, it's possible it just finished thawing out. I've hit up Sprouts and Central Market for fresher birds. To me they have a cleaner taste, but could be coincidence. However these fresher birds are either 5+lbs or under 4. For comps, 4.5lb is good, but I've discovered they are rare around here. I cooked these up at a local comp this past weekend. ~3.8 lb, cooked on a 18 WSM, semi-direct. Brined and injected! 9th place