06/11/2026
Everybody talks about how important hay is for a bunnies G.I. system, But do you know why? 
Give this a quick read;
What is the Cecum?
Why fast fermenting foods are a problem.
The cecum is a large, thin walled pouch located where the small intestine meets the large intestine. It makes up about 40% of the entire GI tract and contains a spiral internal structure that increases surface area for fermentation.
It’s essentially a fermentation vat filled with microbes (primarily Bacteroides) that rabbits rely on to digest plant material they can’t break down on their own.
What the Cecum Does
The cecum’s job is fermenting indigestible fiber, the long, coarse plant material that bypasses enzymatic digestion.
Key functions:
• Ferments cellulose and hemicellulose into volatile fatty acids (VFAs), which supply major energy.
• Produces cecotropes, nutrient rich soft pellets containing amino acids, B‑vitamins, and fatty acids. Rabbits re‑ingest these to absorb nutrients they can’t get the first time through.
• Maintains microbial balance, which protects against pathogens and keeps pH stable.
How the Cecum Works
Rabbits use a particle size sorting system:
• Large, indigestible fibers (>0.5 mm) move quickly through the colon and are excreted as hard f***l pellets.
• Small particles and soluble material (
