Croutons are pieces of sauteed or rebaked bread which are seasoned and cubed used to add flavour and texture to salads and soups.
So can guinea pigs eat croutons, and if they can, how much of them can be eaten?
Lets take a look at their nutritional data and find out more.

In particular, their acidic, phosphorus, sugar, fat and calcium content is of most interest as far as guinea pigs are concerned.
Total Fat 7 gt10%
Saturated fat 1.5 gt7%
Polyunsaturated fat 1.3 g
Monounsaturated fat 3.1 g
Cholesterol 0 mgt0%
Sodium 698 mgt29%
Potassium 124 mgt3%
Total Carbohydrate 74 gt24%
Dietary fiber 5 gt20%
Protein 12 gt24%
Vitamin At0%
Vitamin Ct0%
Calciumt7%
Iront22%
Vitamin Dt0%
Vitamin B-6t0%
Vitamin B-12t0%
Magnesiumt7%
source google
As you can see croutons contain quite a bit of fat in them, but that is about all of the bad stuff.
However, they also contain no vitamin c.
This means that they are fine for guinea pigs to eat, but not often, one to two times a week at the most. However, they hold no nutritional benefit for them whatsoever so are not a food that should be used in a guinea pig’s diet. Just an occasional snack.