Most employment arrangments relationships are what is known as "at will". This means that a company can set the conditions of the workplace much as it sees fit. That is unless doing so would violate the terms of any applicable employment contract or union agreement. Also, no form of that is legally actionable discrimination must be the reason for an employee's treatment. Accordingly, absent the foregoing, you have no claim. That having been said, if you wear dreadlocks as part of your religion, unless it would be an undue hardship on your company's business operations, it must "reasonably accommodate" your religious beliefs or practices, which includes such things as dress or grooming practices (i.e. wearing certain hairstyles such dreadlocks). That having been said, since courts have ruled split on this issue depending upon the specific circumstances of the case, you can contact your state's department of labor and/or speak with a local employment law attorney to be certain of your rights.