Baking chicken. What herb can I substitute for tarragon?

I think that lemon thyme would work very nicely.

Basil, sage, oregano, anything.
I slice lemons thinly and slide those under the skin also.
Good luck!
Cheers
irina

What do you have / what do you like? Most (all?) herbs go well with chicken.

I'm with pierino on the thyme and rosemary. A little sage does well, too. Stick the herb(s) and some butter under the skin of the breasts and thighs and then salt and pepper over the oiled exterior. Stuff the cavity with chopped onion. Let us know what you end up doing!

Thyme or rosemary work well with chicken.