Not exactly sure how you want to change it, but you can open Mansion.gd with a decent text editor, just be sure to make a backup of the file first. Search for "person.work == 'cow'" it will take you to the start of the code that calculates the amount of milk produced by each cow. The variable "production" holds the amount of food produced, so you will want to change how it is calculated. Here are some ways to alter it:

• to change the boost from large breasts change the number in front of "18*globals.sizearray.find(person.titssize)"
• to change the boost from many breasts change the number in "(0.33 * person.titsextra)"
• to change the boost from the manager(will effect hens as well) change the numbers in "(0.4 + farmmanager.wit * 0.004 + farmconf * 0.002)"
• to add a general percentage reduction, simply add something like "* 0.25" to an existing line like the breast size