I have read a lot of information on supplimental feeding in states. In Texas, we can use feeders or food plots as needed. In some states you can use feeders but not during hunting season. Other states allow food plots but not feeders. The best advise I would have would be to contact the state game and fish agency directly, as they would be the only ones I would trust with the real information.
The reason this varies so widely is the perception of what is baiting by each state, and for that matter hunters within that state. It is very difficult to judge hunting or what is required to harvest animals within states if you have never hunted in them. For example, I have hunted in South Dakota, Oklahoma, Texas, Colorado and promise that the use of food plots or feeders in each of these states would be very different and the laws very widely. I have never hunted in NH but I am sure the agriculture of the region, size of the property hunted, season dates, etc. are very different then Texas hunting. My opinion, if you feel it is ethical hunting, you are helping the deer herd, and you are following the local laws, then do what you feel is best and enjoy the outdoors.