Peas are a favourite vegetable in many different countries and civilisations around the world. They are eaten on their own or as part of a culinary dish.
Many people grow them in their pods and then cook them as such.
So can guinea pigs eat peas and if they can, how much of them can be eaten.

image wikpedia
Lets take a look here at their nutritional data and find out more. In particular, their acidic, phosphorus, sugar, calcium and fat content is of most interest as far as guinea pigs are concerned.
Peas, green, raw
Nutritional value per 100 g (3.5 oz)
Energyt339 kJ (81 kcal)
Carbohydratest14.45 g
– Sugarst5.67 g
– Dietary fibert5.1 g
Fatt0.4 g
Proteint5.42 g
Vitamin A equiv.t38 μg (5%)
– beta-carotenet449 μg (4%)
– lutein and zeaxanthint2477 μg
Thiamine (vit. B1)t0.266 mg (23%)
Riboflavin (vit. B2)t0.132 mg (11%)
Niacin (vit. B3)t2.09 mg (14%)
Vitamin B6t0.169 mg (13%)
Folate (vit. B9)t65 μg (16%)
Vitamin Ct40 mg (48%)
Vitamin Et0.13 mg (1%)
Vitamin Kt24.8 μg (24%)
Calciumt25 mg (3%)
Iront1.47 mg (11%)
Magnesiumt33 mg (9%)
Manganeset0.41 mg (20%)
Phosphorust108 mg (15%)
Potassiumt244 mg (5%)
Sodiumt5 mg (0%)
Zinct1.24 mg (13%)
(source: Wikipedia)
As you can see peas do contain quite a bit of phosphorus, a hint of calcium, and are quite acidic. They also contain quite a bit of sugar and a hint of fat.
However, they also contain a very good amount of vitamin c.
With this in mind, guinea pigs can eat peas but only on a once a week basis, because of their calcium, acidic and phosphorus content.
They can also eat the pods that they come in as well.
However, they can only be eaten raw. So do not feed them frozen peas or tinned peas.