To change the breeding, maturation and hatching multipliers you will need to change the following inside the Game.ini file:
[/Script/ShooterGame.ShooterGameMode]
MatingIntervalMultiplier=0.1
EggHatchSpeedMultiplier=32.0
BabyMatureSpeedMultiplier=32.0
LayEggIntervalMultiplier=0.3
BabyCuddleIntervalMultiplier=.1
There are also some breeding settings that can be set by creating a custom command line.
Please note that if the [/Script/ShooterGame.ShooterGameMode] line is already present in the Game.ini, then you don't need to add it again.