Loosen the chicken skin with your hands or you can use an upside down spoon to separate the skin from the meat. Take some care not to rip the skin.
Add spoonfuls of the wet rub under the skin, leaving about a teaspoon to rub on the outside. Using the back of a spoon or your hands smooth the wet rub under the skin while rubbing the remaining wet rub on the outside of the chicken.
Place your zested and ½ juiced lemon in the cavity of the chicken along with the fresh herbs
To the bottom of your slow cooker add the carrots and onions to create a bed for the chicken and place your chicken on top of the veggies
Cut the second lemon in half and place in the slow cooker with the chicken and veggies
Set the slow cooker to low and cook for approximately 5 hours, until the chicken reaches an internal temperature of 165 degrees F.
For crispy skin
Set your oven to broil with the racks set with enough room to allow your chicken to be close to the broiler, probably 1 slot above the middle.
Remove chicken from the slow cooker and place on a baking sheet, place under the broiler for 5-7 minutes to crisp and brown the chicken skin.
For gravy
Pull 1½ cups of the drippings from the slow cooker and strain into vessel with a pour spout and set aside.
Melt 2 tablespoons of butter in a medium saucepan over medium heat until the butter starts to bubble
Slowly add the 2 tablespoons of flour melted butter, whisking constantly to make a roux. Cook the roux until the color begins to shift to golden.
Slowly add the 1 ½ cups of strained chicken drippings to the roux, whisking constantly until there are no lumps and cook until the gravy thickens
Taste, add salt and/or pepper if necessary
For an extra luxurious gravy, finish by stiring in 1/4 cup of heavy cream