I have wondered about the mining rule, that coins are treated as income at the time they are mined. If I have a chicken and it lays an egg, is that a taxable ev

I have wondered about the mining rule, that coins are treated as income at the time they are mined. If I have a chicken and it lays an egg, is that a taxable event? If I have a 3D printer machine and it produces a widget, is that taxable also? From my understanding those are not taxable events even though the egg and widget have known market values at the time produced; only when you sell the egg or widget do have ordinary income tax. Even though cryptocurrency is property like the egg or widget, it is not treated the same way when mined. If I understand correctly, mined crypto is double taxed: once when mined and again when you sell/exchange it.