You can always 'take' hooves from another horse and with a bit of tweaking, add them to your little stumpy pony.
Recently I did a blood bay Arabian who needed his hooves re-drawn and re-painted due to lots of grass. This was my step by step process of how I did it:
1. Create a new, transparent layer. Colour select the various parts of the available hoof using the eyedropper and add some splotches near the legs so you can continue to use these colours in the future.
2. On the same layer, use a solid black, red or white pen and draw the outline or guiding shape of your hoof. Remember than hooves are at an angle and go from wide to thin. They are also never completely straight on the edges.
3. Create a new layer. Fill in your hoof with a base colour. If the leg has a white marking, the hoof will be a creamy/white/peach colour. If the leg is solid (no markings) it will be grey or black. Try not to use true black for the base. White legs with black markings on the coronet band will usually result in a dark line on the hoof.
4. Bearing in mind your direction of light, use the burn tool to add some patches of darker colour. Use a low strength and work n layers. The hoof is usually darker near the sole and at the heel. I like to add some patches, then us a line brush and add some streaks. Reference images are very helpful here!
5. I usually take 2 colours lighter than my base and 2 colours darker. Using a line brush such as the 'splash' brush and the 'spray paint style' brush I use a 20% opacity and add some lines, darker areas and lighter spaces. I work in streaks and use the smudge tool to soften edges and ends. If I am adding dark lines to a light hoof, I also use the blur tool to soften the edges and to blend colours a little more.
6. You can mess about changing the blending mode, brightness, contrast ect until you find a nice result. I often leave the blending mode on normal and just work with the paint, dodge/burn and smudge tools. I try to work in short strokes and clicks when I can.
The finished result:
https://imgur.com/a/A0U9brB
Don't forget to remove your colour swatch and hoof line layers when you're happy with the hoof. I don't usually worry about drawing the hoof around grass or rocks and will layer or draw those over the hoof afterwards.
Evening Thunderstorms, Hail Possible
