Chop half the tarragon and blend with half the butter.
Put the mixture inside the chicken, and the rest of the butter into a fireproof baking dish to melt.
Put in the bird, making sure that it is coated in the butter by turning it once or twice.
The oven should be fairly hot for the first 20 minutes or so of cooking.
Turn the bird fairly frequently.
Lower heat after 30 minutes, and allow another 20-30 minutes for the bird to brown properly.