A more thorough explanation:

Schechter Poultry Corp. v. United States was a Supreme Court case that declared a provision of the National Industrial Recovery Act (NIRA) unconstitutional. The NIRA allowed the President to approve "codes of fair competition" for industries, including the poultry industry. These codes regulated minimum wages, prices, work hours, and other rules that would apply to entire industries. The Court found that this violated the Nondelegation Doctrine and the Commerce Clause of the Constitution.

The Court ruled that Congress had overstepped its bounds by regulating local commercial activity that only had indirect effects on interstate commerce. Additionally, by giving the Agency for Industrial Recovery broad powers to ensure "fair competition," Congress had effectively delegated legislative power to the Executive. The Court held that Congress cannot delegate legislative power to the President to make whatever laws he thinks may be needed for the rehabilitation and expansion of trade or industry.

For example, if Congress passed a law that allowed the President to set prices for all gas stations in the country, the Supreme Court would likely find this unconstitutional because it would be an overreach of Congress's power and would delegate too much power to the President.