Why is it birçok and not çok?
Çok is right too.
did ''boyun'' mutate to ''boynu'' is it a loanword ??
Yes, boyun turns into boyn- if you add an ending that starts with a vowel.
It's a pure Turkish word. Other Turkish words do this, too, e.g. ağız "mouth", burun "nose", alın "forehead".
So it's not only loanwords like "fikir, fikr-" that do this.
So it can't be "boynunda birçok yaralar var" ??
After birçok you have to use singular.
What's the Turkish for "vampire"? LOL
Who says that, wound means knife wound?
I am afraid there many example like this that did not bother to report
Boynunda çok yara var is accepted.
I am interested whether there are any alternative ways to say the same thing, for instance 'Onun boynunda pek çok yara var'?