It's certainly possible they can swallow a chicken neck whole... which is why I don't give them to my gang, but also, mine don't get the teeth scraping benefit from chicken neck b/c it's gone in about two crunches. I have read many stories about dogs swallowing turkey necks whole, which are huge, but they don't choke or anything. just uncomfortable for a while. dogs don't really chew things like we do, if it's a size that will fit down their throat, they'll swallow it. That's the only requirement for them. If you're dog isn't a gulper, though, you'll be fine with a deer neck or something large and even if they do gulp it, it's not going to kill them it's just not going to give them the teeth scraping benefit. I'd never hold their bone for them! Dogs can tell when you're nervous and will definitely gulp if you're holding on it. I give mine their bones, respect them and back off while they eat but am always near supervising them, and they've never even come close to choking on a bone. Dogs are made to eat bones. The boneless meat is where I've had the problems with and they where man-made errors in that I cut the piece of meat just to wear they'd swallow but then wouldn't be able to get it down. You kind of learn how to work with each dog based on their needs. But, seriously, bones are the safe part. Even if they don't chew them, it still digest.
I find pigs feet good for cleaning teeth. I also like deer neck but you probably won't find that in the store --Pork ribs can be good, too. Beef, I would assume, too but mine can't chew threw the bone, or don't want to so I don't bother. Lamb shank is great for the teeth. The bones only help reduce the plaque, however. The raw meat, big meaty pieces like pork shoulders, and biting in and having it floss their teeth is the best thing for their teeth, and the reason most raw fed dogs have pearly whites! The bone will help reduce plaque, but the meat keeps it away entirely.
When I got my sheltie, her progress report said she her teeth were in very poor condition. A year later, she went back to the vet, and now her teeth are "in perfect condition." I truly love the fact I'm feeding them a species appropriate diet and they're getting the benefits nature intended them to have! Best of luck to you and enjoy