Complex sentence: Vent pecking clearly causes pain and distress to the bird being pecked, tearing of the skin increases suceptibility to disease and may become cannibalistic leading to evisceration of the pecked bird and ultimately, death.
Split into simpler sentences: Vent pecking clearly causes pain and distress to the bird being pecked. Tearing of the skin increases suceptibility to disease and may become cannibalistic leading to evisceration of the pecked bird and ultimately, death.