Since you have 3 dogs next door to you, I absolutely say you are correct to worry. A 4 foot tall fence is not too high for chickens and may not be too tall for a lot of dogs! Better safe than sorry, unless you are ok with some losses. I free range mine, but I don't have dogs right next door that run free all the time. I do have a neighbor that has 2 dogs that are fenced in a nice large pen that is far enough away from my house that the dogs cant see into my yard. Since they can't see the chickens I don't worry too much. I know it is possible that they could get out and come down to my house and get after my chickens, but I am willing to run the risk since I primarily got chickens to help with tick control. If they are always in the run they can't do what I originally bought them for. So far I have had no losses. Hope I didn't just jinx myself...