roosters are very competitive - if one crows, the others want to outdo him. You are lucky they only do it three times a day. Roosters can handle 10 hens each, so if you buy 80 hens they would be busy with them and maybe not crow so often.
Then again once hens enter the picture - crows start to fight with each other.
Then again once hens enter the picture - crows start to fight with each other.