I think that's the problem here, movement of any kind is the enemy of stacking and you have to be really lucky for a live creature to pose absolutely still for a series of images to be stacked.
Using flash is the key here as it will enable you to use a lower shutter speed and consequently a smaller aperture to get increased depth of field, at least it works that way for me.
I knew nothing about flash until I started doing macro. I still only know slightly more than nothing but just enough to enhance my macro shots. It's worth learning about.
When I was using Olympus for macro I bought a Smallrigg cage and was able to attach a small flash gun very easily to it with a flexible extension arm, I still do this for my Sony.
