Add chicken to a large pot and fill with water until it is submerged at least 1 inch. Add 2 teaspoons sea salt and bring to a boil; then reduce to a simmer and cook, partially covered, for 30 minutes. Add onions, garlic, carrots and acorn squash and continue to simmer for another 40 minutes. Remove chicken from pot and shred the meat, using two forks. Add meat back in the pot along with the kale. Simmer until kale is wilted, about 10 minutes. Season soup with sea salt and pepper, to taste.