"Give me the chicken."
Translation:Gib mir das Hähnchen.
No, not correct, as you can see here.
For du, the command form will have a changed vowel (e to i or ie) if the normal form does as well, e.g. geben, du gibst: gib! or sehen, du siehst: sieh!.
But a change of a or au to ä or äu is not in the imperative: halten, du hältst: halt! laufen, du läufst: lauf!
When you are speaking to several people, the imperative is gebt!.
When you are speaking to one person, the imperative is gib!. (With the same vowel change as in du gibst.)
geb! is not the correct imperative form for any listener in standard German. (Though you may hear it from some native speakers, especially in the north. I'd consider it uneducated, though.)