Do not include their income on your tax return.  Their income will go on their own returns, if they are required to file.  If this is their only income, it is not required to be reported anywhere.  

In case they do have other income, you may wish to share these with their parents to determine if a tax return must be filed.  

thank you so much, the kids are only 10, 11 and a special needs 20 yr old with no other income.  I appreciate your response, just wanted to do the right thing.