In a med saucepan, place chicken and enough broth to cover (add water if needed) and bring to a boil. Decrease heat and gently simmer until chicken is cooked through (about 20 to 25 mins). Transfer chicken to a bowl to cool (I put it in the fridge while I'm working on the next few things). Reserve 1 1/4 cup of broth and refrigerate or freeze the rest for a later use. When chicken is cool enough shred into pieces.
Heat the oil in a large pot on med high heat. Add leeks, carrots, and 1/2 tsp of salt and cook, stirring often, until the veggies soften, about 6 to 8 minutes. Stir in flour and let cook for about a minute. Gradually stir in wine and broth and bring to a boil. Add peas, parsley, tarragon, pepper, chicken, and remaining salt. Stir well. Transfer chicken mix to two 2-cup baking dishes and preheat oven to 375* F place puff pastry over the top of dishes, trimming where needed, to let the pastry hang over about an inch. Cut a small vent hole in center of pastry. Place on a baking sheet and bake til golden brown and crispy on top. About 35-40 mins.
Or if your using the crescents, I use the cut crescents but you can use the crescent sheet. Do your best to seal the cut between two triangles and cut in half. You use both pieces for one pie. Stretch it out the best you can to cover the dish. Slice a vent hole in center, then repeat with the other half stretching the best you can I lay it over the top with the corners opposite the bottom dough. Cut vent in same spot as the bottom. Cook as directed on package of crescents. About 17 mins at 375* F. I always roll up the extra crescents and bake them along with the pot pies and they all come out golden brown and delicious!! Hope you enjoy.