They did a great job with my meat chickens last year. But they are not mobile processing this summer so I am going with another professional from around the same area - the little town of Pittsfield, NH. Mike's Meat Shoppe was highly recommended.
https://sites.google.com/site/otherpeoplespoultry/
Other People's Poultry - owned by Andrea Tomlinson
They have a mobile poultry processor, and they also will process right at the location in Northwood. Whatever you prefer.