Are you going to talk to them? More importantly, are they going to talk back? I've done this and they just get freaked out when they hear you talking from nowhere, they also get freaked out if you zoom the camera in or out lol.
I use a Hikvision DS-2CD2432F-IW to watch my dogs inside. Sure does freak them out but if they're doing something they shouldn't be, they knock it off real quick. I wouldn't recommend it for 2 way audio though.