This isn't a bug with Minecraft. This is because you didn't install OptiFine, which is required for the texture pack. Always read the descriptions of resource packs to check if they need it. You can install OptiFine at: https://optifine.net/downloads
If you do have OptiFine installed, make sure that "random entities", and "custom entity models" are enabled. If it keeps happening, try removing any other resource packs.
rat consumption
This isn't a bug with Minecraft. This is because you didn't install OptiFine, which is required for the texture pack. Always read the descriptions of resource packs to check if they need it. You can install OptiFine at: https://optifine.net/downloads
If you do have OptiFine installed, make sure that "random entities", and "custom entity models" are enabled. If it keeps happening, try removing any other resource packs.