No. They lived with you less than half the year. A child of a taxpayer can still be a “Qualifying Child” (QC) dependent, regardless of his/her income, if:
1. He is under age 19, or under 24 if a full time student for at least 5 months of the year, or is totally & permanently disabled
2. He did not provide more than 1/2 his own support. Scholarships are considered third party support and not as support provided by the student.
3. He lived with the parent (including temporary absences such as away at school) for more than half the year
4. He must be a US citizen or resident of the US, Canada or Mexico
5. He must not file a joint return with his spouse or be claiming a dependent of his own
6. He must not be the qualifying child of another taxpayer; such as the foster parents.
If the foster parents aren't going to claim them, you should. If they are going to claim them, you can try too and the IRS will sort it out