The picture I tagged are of a horse after I tried to change their mane & tail. When I clicked undo (and put the horse back to being maneless and tailless) the horse returned to it's proper colour. The horse also would appear black in game when I accepted the CAS changes.

I have tried clearing the cache. Lowered the setting of the graphics. I took out my mods folder. Replaced my game with a back up I had. Uninstalled and Reinstalled Pets.

Pets worked for about a fortnight on this laptop really well before this Glitch popped up. All I downloaded just before this happened was the Appaloosa Plains routing fix from this site, and I on't think that it is to blame.

[Edit]: Dogs and cats are doing it too.

I have had that happen in CAS with sims and reassigning another skin cleared the issue. Often I see this with deer and raccoons and sometimes other pets. Most likely the sim has a broken or corrupt outfit assigned to them and when the game attempts to render their physical body it is unable to do so. Using Fix Invisible Sims in Debug Enabler brings them back. However, Re the deer, raccoons and other pets (pets in the Service Pools) I've noticed after the overnight cycle with the next day the game reassigns the skin and often that instance needs another DE fix. For human sims it is more than likely "bad cc". I am not sure if it is just custom skins or the fact that the game (The Pets EP) is broken when it comes to those service animals.

I had all my mods removed at one point so I dont think it could be bad CC. I'm reinstalling the base game to see if that'll help any. Might reset what happened

Turns out my graphics card can't handle the game... I'm looking into buying an external one, I believe that shall fix it. If not I'll just have to hope sims 4 has horses in it...

Intel(R) HD Graphics. The one that came with the laptop, I thought it would be fine as My toshiba could run the game alright.