Empty Headed Dogs?

Translating can be a tricky job. I'm so not a translator at this stage in the game! But still, things come funny to me at times (including the English language...I don't think we say that things come funny to us - that would be a translation out of Turkish to English!). About a month ago some friends and I came across this sign while hiking. We have a stray dog problem in Ankara. But directly translated - we have a problem with dogs who have empty heads. Stupid dogs? No, simply dogs who have no owners...