Nope
Probability HAS to reduce to get more roosters. 4 roosters is not MORE likely than 2 or 3.
1/16 - 6.25% - 4 rooster
2/16 - 12.5% - 3 roosters
3/16 - 18.75% - 2 roosters
4/16 - 25% - 1 roosters
I believe you are right. I just need to work the formula out.