I think it may depend on what type of deer, elk, moose, etc the antler came from. I bought two, I can't remember what they are, and they are hard as rocks. Mine have not penetrated them yet. The ends are just ground down a bit. It may also depend on what time of year they are harvested.
From what I know, if the antlers are naturally shed in the late fall/early winter they will be hard because they no longer had a blood supply and were dry and dead when lost, but if cut off while they still had a blood supply the antlers will be softer.
What kind and from who did you get them? I have quite a few of them and they have never been able to do that
One deer and one elk both were split pieces from Petsmart.
I don't get the split ones…. so maybe that is why I have not had a problem
This is so good to know! I've never offered antlers, but I'm going to give them a try. After pig's ears and snouts, the gross factor kinda recedes. Where's the best place to buy ones that don't/aren't split– online?
I get mine from here and I get the large size
http://www.bestbullysticks.com/home/bbs/smartlist_25/antlerz.html
Great– thank you! That's where I get bully sticks. Do you think the large size would be good for a puppy?
My babies chew on the large size…. 
but you could get 1 or 2 of the medium ones to start while he/she still has puppy "razors"...... I like the other place too, as my adults like the Junior Jack Chaws too and have not been able to break them apart.
They are great I bought my girl one and she loves it !! , cost me about $14 for a smallish one and I was told they are edible as well
Same goes with a "rawhide" I got her a Bosleys ,it's made %100 out of potato so it's also totally edible
It's lasted her a good week and a half maybe two since she's got a quarter of it left 
But I love love the deer and or elk antlers whole or split lol she decided which one
Well Tilly certainly likes Deer atlers too - last time we took her a walk in the woods directly behind our house she disappeared into some bush, and appeared with some antlers in her mouth - unfortunately they were still attached to a well-rotted head…. so she didnt get to keep them...
Haaahaaa! just gotta love the canine heart!/stomach!!! better she trotted off with them rather than just rolled in it and have you wonder why she smelled so bad while she was up on your couch/bed….!:)
