Silkies with high vaulted skulls are more likely to have problems if the right/wrong spot is pecked or bumped than those without the vault. There is a hole in the top of the head, much like a human baby's fontanel, but it is only bridged by an arched, narrow strip of bone and doesn't ever close in. One can find pictures of silkie skulls on the internet. The brain protrudes into that vault. It appears to me heat/cold makes a difference as to how much it protrudes at any given time. Those with high vaulted skulls have larger crests for the most part, but not all silkies have vaulted skulls, and I've had many that have pretty large crests anyway. At least half of my silkies have vaulted skulls to one degree or another; you can tell at hatch which ones do, and you can feel the protrusion the rest of their lives. I've only had a few with neurological problems because of the vault, and unless the blow that caused the problem kills the bird, you can usually relieve the problem with rest, vitamin e, and/or PolyVisol drops for children (without iron). Some people give them prednisone and other mdications. Even some birds that have a fairly severe injury, causing them to "sky gaze" (wry neck), can often be treated successfuly, but are still prone to other injuries because of the lack of brain protection, though they may never have problems again.
