In mixing bowl, beat cream cheese, milk, dill, salt and pepper until smooth. Stir in chicken, celery and onions.
Unroll crescent dough, separate into 12 rectangles, place on baking sheet and press perforations together. Spoon 1/3 of mixture into center of rectangle. Bring edges to center and pinch to seal. Brush with butter and sprinkle with bread crumbs.
Bake until brown, approximately 20 minutes at 350 degrees F.