Duck sound is adapted from "BIRDS IN AMBIENCE mono and stereo", available under a Creative Commons Attribution-Noncommercial license.
Goat sound is "goat choir - minor third- two goats bleating simultaneously.WAV", available under a Creative Commons Attribution license.
Alpaca sound is adapted from "Alpacca makes a noise whilst scratching his throat.wav", available under a Creative Commons 0 license.
Llama sound can be found here.
Sheep sound is "Sheep.flac", available under a Creative Commons Attribution license.
Goose sound is "Goose - Horn 1 - 96kHz.wav", available under a Creative Commons 0 license.
Chicken sound is "Chicken Single Alarm Call", available under a Creative Commons 0 license.
Pig sound is "Pig004.wav", available under a Creative Commons Attribution license.
Cow sound is "Cow.wav", available under a Creative Commons Attribution license.
Correct answer sound is "Ring.wav", available under a Creative Commons 0 license.
Incorrect answer sound is "Bad Beep (Incorrect)", available under a Creative Commons Attribution license.