Wash the chicken well, removing any excess fat pockets, and trimming the skin lightly if desired. Loosen the skin from the breast and leg meat carefully. Take out any innards trapped in the bones of the cavity and let fresh water clear it out. Dry the chicken well, all of you.
Combine the thyme, garlic, salt, pepper, and olive oil in a bowl. Stir well, adding the lemon zest, and strained juice, if desired.
Slather some of the mixture into the cavity of the chicken. Put in the chopped bacon.
Massage the remainder, as deeply as possible, into the breast and leg meat, reaching deep into the drumstick, and around the thighs.
Tie the chicken legs. If any of the skin tears along the seam of the breast, tape it back together with toothpicks.
Fit a roasting pan with a rack and add broth to a level that will not touch the chicken.
Lay in the hen, breast side down and roast at 350 for 40-50 minutes.
Retrieve the chicken from the oven, turn, breast side up. Continue roasting at 350 until done, and the breast registers 165 degrees in the thickest part. Make sure to take its temperature periodically, I find that people have other things to do and let the chicken cook lazily, thinking that it is never going to be done, and then go to check it, to find that it has already ruined. Check it, at least twice.
Transfer to a plate, cover loosely with foil, and discard the rack. Transfer the drippings to a measuring cup. Retrieve off most of the fat, you can save some out to add back to the pan, if you feel the desire to have it a little richer, I don't really like a fat gravy.
Taste the drippings, add more broth if desired.
Do not have it too salty. Mix some cornstarch into a bowl with a little water or room temperature stock (about 2 tablespoons starch).
Bring the drippings to a simmer in a small saucepan. Let the pan be slightly below the boil, and add in the starch, by degrees until it is thick and proper.
Cook, if needed, then serve with the roast, carved up at table.