I raised 2 batches of Cornish X last year. The spring group was processed at 8 and 9 weeks (I did half one weekend, then the rest the next weekend). The week before the first processing I had a lot of crowing. Some of them were pretty funny to hear, but some were very strong sounding. My fall batch was processed at 7 and 8 weeks old, and I never heard even 1 attempt to crow. My first batch this year is 5 weeks old now and while silent, I do have a few boys that are more aggressive than the past. Mock fighting, attacking the broom as I shoo them back in their pen at night, nothing that I need to worry about, but it is strange to see the vast differences in personalities and behaviors in the different batches.