For the Gamma Broodmother, the easiest (but still pretty safe) way to defeat her is to have 19 megatheriums with as even of a male and female mix as you can get.(for mate boosting) Make sure that all of your megatheriums have at LEAST 10k health, then level any extra points you can get into melee damage. The creature cap for the brood battle is 20, don’t worry, I didn’t forget your 20th creature. A Yutyrannus will fill that slot! You’ll want to make sure that your yuty has good stamina so that it can deliver buffs to your allies and debuffs to your enemies. Keep in mind, this is for Gamma, I’m not too sure how this method would work with Beta and Alpha. Good luck!