This is a nominal price that is included in the minimum breeding price calculation. Currently, the base breeding price is set to 0.00267 ETH.
This does not mean the minimum breeding price is 0.00267 ETH, rather it acts as the base to determine what the final breeding price will be depending on bloodline, breed type and the duration that the sire is in the stud farm.
Below are the current minimum fees in ETH:
Disclaimer: Base breeding price and minimum fees displayed are rounded values and not exact.