Quick answer
Calculate tier distance, inventory credit, and the remaining merge deficit
Enter the ratio shown in your server, your current and target tier numbers, and owned counts at every intermediate tier. The calculator multiplies across the distance, credits inventory, and returns required lower-tier chickens, merge actions, surplus, and a space warning.
This Chicken Farm merge guide explains every input before the calculator: tier distance controls chain length, the current-server ratio controls each merge, and owned intermediate chickens reduce the remaining deficit.