A lady at the mouse forum I frequent was kind enough to provide me with the following information:
Cinnamon is not a good thing to feed mice...AT ALL.
Coumarin is the toxic substance in the most easily found kinds of cinnamon. It is a naturally occurring substance, and is a blood thinner. Toxicity damages the liver and it does not take much to reach toxic levels.
On top of that, Coumarin is also popularly used in rodent pesticides, since mice and rats eating it suddenly fail to produce Vitamin K, and go through renal failure as a result.
In fact, most spices should never be used in a mouse's food.
ETA: Thus, if you feed your mice dried bread occasionally/as a staple, avoid cinnamon bread or any other foods that contain it and other spices.
Do you mean "coumarin" or "coumadin"? I know coumadin is frequently found in rodenticides, but not familiar with coumarin
Ferrets: Contessa Kitties: Watson, Oskar DIP Sinnead, Vincent, Boris, Zeus and Athena, Willow, Mr. Frodo, Indie, Lucrezia, Judge, Odin, Miss Emily, Suki, Cody, Aristotle, Butterscotch, Frankenfurter. RIP Herne, Ligeia, and Mr. Stubbs
Thank you, Hannah. I've only mentioned it a couple of times elsewhere but I'm actually deeply involved in the process of doing research for making specifically balanced and raw (all from nature ingredient) dry mixes for each species of rodent - mice, rats, gerbils and hamsters. I plan to post each dry mix with the info when I'm done, but if you need some info before I've finished I'd be truly happy to share with you what I've come up with for my mouse thus far - I'm also working on a rat mix because next month we should be getting our first rats from a great breeder here!
(P.S. No dry mix is complete without some daily veggies/fruit and the occasional cricket or bit of egg for protein.) ^_^
Many of the above compounds (specifically the 4-hydroxycoumarins, sometimes loosely called "coumarins") are used as anticoagulant drugs and/or as rodenticides which work by the anticoagulant mechanism. They block the regeneration and recycling of vitamin K. These chemicals are sometimes also incorrectly referred to as "coumadins" rather than 4-hydroxycoumarins (Coumadin™ is a brandname for warfarin).
Some of the 4-hydroxycoumarin anticoagulant class of chemicals are designed to have very high potency and long residence times in the body, and these are used specifically as poison rodenticides. Death occurs after a period of between several days to two weeks, usually from internal hemorrhaging.
Vitamin K is a true antidote for poisoning by these antirodenticide 4-hydroxycoumarins such as bromadiolone. Treatment usually comprises a large dose of vitamin K given intravenously immediately, followed by doses in pill form for a period of at least two weeks, though usually three to four, afterwards. Treatment may even continue for several months. If caught early, prognosis is good, even when large amounts are ingested. In the sort term, transfusion with fresh frozen plasma to provide clotting factors, provides time for vitamin K to reverse enzyme poisoning in the liver, and allow new clotting factors to be synthesized there.