Most health conditions which affect guinea-pigs first become apparent when they lose weight, and as such it is helpful to weigh your guinea-pig weekly so that you can become aware of normal weight fluctuations (up to 1 ounce per week is fairly normal) and detect any underlying health conditions early.

An adult male guinea-pig should weigh in the region of 900g to 1500g, and sows should weight between 700g and 1200g. As you can see, there is a huge difference between individual guinea-pigs, depending on their diet, exercise and genetics.

Any weight loss greater than 1.5 ounces in a week could indicate poor health, and if your guinea-pig’s weight continues to decrease at such a rate or decreases by more than this in any given week, your pet should have a thorough veterinary examination. When your guinea-pig seems to be losing more weight than normal, it’s a good idea to weight them more often (perhaps even daily) in order to monitor it more thoroughly.