Yes, in5 supports animated GIFs.

If you want to include a GIF in the output, simply make sure that it's not cropped by the frame in InDesign.

If the image is cropped, in5 will think you want to re-render the image.

If the GIF fits into its frame, then in5 will simply pass the GIF file into the output.

The quickest way to fix the frame is to select the object on the page, right-click and choose Fitting > Fit Frame to Content.