>>I am expecting to recieve a group of these in the next week, but would like some advice on housing, I need to know temps, humidity, feeding etc. Haven't kept these before, so any advice wold be good, I have had Bitis sp. before, so am not a novice with hots.
Well, a lot has already been said about this species. I'll just add my $.02 on a few things as well.
Housing - As has already been said, N. nigricollis are the biggest spitting cobras on the planet. Adults can be anywhere from 6' to 8' (maybe even longer), and have decent bodily girth. Therefore, they will need a very roomy enclosure. I currently have 1.1 juveniles that I've had since about last Nov or so. When I got them, they were both around 1'. Now, they are both around 2 to 2.5', so they are growing fairly rapidly. They'd be growing even faster if I fed them more. Also, them being spitters will have to be taken into account for housing. Obviously there needs to be no direct line path from their head to your eyes at any time. These snakes are dead on accurate. Even my juveniles, any time they spit, hit the glass exactly where my eyes would be. Though I've never experienced it (thank goodness), I've had black neck cobra spitter spray described to me as feeling like "...a dumptruck full of sandpaper being shoved into your eyes" by someone who has. Doesn't sound very pleasant to me, that's for sure. If you've ever seen pictures of them, note the very large venom glands. As people have already notated, this species especially seems to have an unending amount of venom. I think rinkhals would be the only species of spitter that could beat them for nearly unending yield. So, what was all that for again? Oh, right. No screen top, no screen side, etc etc. Otherwise, you might just find out for yourself what it feels like. Oh, and also, N. nigricollis is one of the hotter of all Naja spitters and has one of the most destructive venoms, so just don't take any chances with them.
Temps/Humidity - Black necks obviously come from Africa. They require a fairly high temperature, I keep mine at about 80 to 85. Humidity is usually just what we have here in Arkansas. I've only once ever had a problem with a shed, and that was the female leaving on an eye cap. Not fun though! I had to restrain her and gently rub it off. She was, however, surprisingly cooperative during that time (her head was always pointed away though, obviously). Since then, I haven't had any problems. In fact, I think at the time that happened I was having humidity issues with my snake room because of a space heater used to heat the room during winter. Humidifiers definitely help during that time.
Feeding - As has already been vouched for, this is the time you should watch out. I'd say my black necks have the "typical" cobra feeding responce....that is, they will come flying out of the hide to grab the rodent or whatever else is in reach once the smell of food comes close enough. I've had them latch onto the hemostats because they smelled like rodents. Also, I know they say spitters ONLY use their spitting abilities in defence, but once when feeding one of mine a live largish hopper mouse, the snake first spit at the mouse, to which the mouse began to react pretty nastily, then the snake grabbed it. So, in that one case at least, the venom seemed to be used tactically. Who knows, maybe these snakes are a bit smarter than most people think.
Anyway, all in all this is, IMO, a very neat species to work with. They've quickly became one of my favorite Naja. They seem to settle down well as well, because I've only had mine since last Nov and they've pretty much stopped hooding or spitting. Makes for a little bit more boring snake (LOL!) but I think I can live with the trade off.
-Chance