Doesn't it? Under 'hair' that site says that the sample must have follicle or roots attached and that cut hair will not produce significant DNA. Do you want to know whether any DNA can be got from it though that is not 'significant' ?
However, Nicolaus Copernicus, the 16th century astronomer accused of heresy by the Catholic Church, was positively identified a couple of years ago by a single hair. The DNA, extracted from a hair found in a book known to be owned by Copernicus was sufficient, when compared to DNA extracted from a femur and tooth from remains found in a Catholic cathedral in Frombork, Poland, to identify the remains...
I was watching CSI and they aid they had to take 10 hairs from a suspect to make sure they got one with a root on it. Whether this has any basis in fact is another matter.
You can have hair analyzed for y-DNA and mitochondrial mtDNA. For mtDNA analysis, you can just use the hair itself. However, for y-DNA you must get the "root" or "bulb" of the hair. The root contains the nuclear DNA which includes y-DNA. You will also see discussions about the "shaft." The shaft is the hair without the root or bulb, and thus without the nuclear y-DNA. Trying to retrieve DNA from hair shafts is difficult and time consuming and could add costs to any tests. There is a lab that specializes in extracting DNA from odd sources such as licked postage stamps, envelopes, ancient artifacts, etc. If this lab finds DNA from hair, they could extract it and then forward it to another lab for Y-DNA testing