Unfair is not the same as illegal. It may well be unfair to do what you describe. However, it would only be illegal if--1) There is an employment contract or union agreement which requires work to be distributed evenly, guarantees certain minimum hours, projects, or pay, etc.2) The employer is discriminating against employees due to a protected characteristic. Under federal law, it is illegal to discriminate in employment due to employees' race, religion, age over 40, sex, or disability. Illinois law adds the following protected categories: national origin, citizenship status, ancestry, marital status, arrest record, military status, sexual orientation. Unequal treatment on any of these grounds would be illegal.3) The employer is retaliating against some employees because they made a protected claim (e.g. for overtime, or that they were suffering discrimination) or used a protected benefit (such as FMLA leave).However, apart from 1) - 3) above, an employer could feed all the work to one employee and send the rest home.