The sentence "According to Rachel McCrystal, factory farming poses many dangers to farmed animals, human beings, and the planet as a whole." uses the signal phrase "According to Rachel McCrystal" to introduce the cited information.
The sentence "Rachel McCrystal, Executive Director of Woodstock Farm Sanctuary, notes that factory farming is problematic for the baby animals it harms, the humans who work there future of our planet." also uses a signal phrase "notes that" and provides attribution.
However, the first option is a more direct and common way to signal a citation within a sentence.