I'm putting an end to this glue conspiracy right now! : r/mylittlepony
Is Glue Really Made from Horses?
Although glue could technically be made from any animal, horses are large and muscular, so they tend to have a lot of collagen. Through processing, collagen can be made into a gelatin
Animal glue - Wikipedia
How Did People Make Glue Out Of Horses?
How Did People Make Glue Out Of Horses?
Are Horse Parts Really Used to Make Glue or Is That Just an Icky Rumor?
The Truth About Horses and Glue - Facts & History - Helpful Horse Hints