Put all ingredients EXCEPT the Achiote oil in a blender. Liquefy. Add the oil and stir. Do not blend in the oil as it tends to change the consistency. I just stir it in after. Set aside.

Butterfly the chickens (2 halves) and remove spine and any innards. Wash and dry. Cut a small slit near the thigh joint (it will cook through better in that area). Make sure they are washed and dried.

Add chicken to a large 2-gallon Ziplock bag.

Add marinade and seal. Refrigerate overnight (at least 24 hours)

Remove the chicken from the bag reserving the marinade in a bowl.

Melt the butter in a pot on medium heat. Add the reserved marinade and bring to a low boil to kill any bacteria. Set aside for basting.

Roast on the grill (Green Egg/Kamado Joe best) over indirect heat at around 360 degrees skin side up. Place them near the outside of the grill, breast side closest to the edge away from the main heat. Baste with the butter mixture every 15 minutes.

Once chicken is around 157 degrees or so, toss them on the direct flame for a bit for a nice char. This will bring the temp up to around 160-165 degrees and they are done. Note that this step is optional. If you like the color and feel of the skin, there may be no need to do this step. Personal preference as long as the chicken is about 160-165 degrees.

Carve up and serve with rice and beans. Add a tomatillo salsa on the side.