Hello! My dog is alone every day for about 5 hours. We've had a strict routine since he was 6 months old (he is 2 now). We take a long walk and play fetch every morning for at least 1 hour before he needs to stay alone and before I go out I give him a special treat he needs to dig out of a toy contraption I made. My neighbor recently told me that he barks when left alone. I got a camera to watch him and he is mostly fine. He doesn't even pay attention to me leaving as he is busy getting his treat out. He then dozes off. But as soon as he hears a noise, he jumps up and starts barking and sometimes even howling. He does that for about 5 minutes and then stops... until the next noise comes. I have a white noise machine but it doesn't seem to help. I live in an apartment building with lots of neighbors and noises throughout the day. I don't know what else to do to stop him barking and people complaining. Any ideas will be appreciated. Thanks!