My guinea pigs have not lost any weight but I am just curious about what the ideal weight should be. Both my guinea pigs are 3 months old and weigh 750 grams, usually gaining 50 grams a week. Many websites say that adult guinea pigs weight 900-700 but mine are already more than the minimal weight for an adult sow. I do not overfeed pellets, only 1 tablespoon a day, so maybe they will just be big adults? I also want to know what ideal/good weights are while they are growing, like how much they should weight when their 4,5, and 6 months old.
Hi! Since the natural weight/size variance is so wide in guinea pigs, weight charts are unfortunately not worth their paper!
If you feed your babies on the generous side, they will come near their adult weight more quickly, but then stop growing faster sooner than youngers on a moderate diet.
Key is not a chart with ideal weights, but a good balanced hay and not veg/pellet based diet without lots of extra treats as well as checking around the rib cage whether your piggies are a good weight/size ratio and are not overweight (too much or too little fat around the ribs). We call this the 'heft' - and it works for all body shapes and ages as this is how you can measure whether you are in the right ball park for your individual piggy.
A good diet is also key for extending the life span in those healthy guinea pigs that do not develop a major medical problem in younger life. While keeping an eye on their weight is an important health monitoring tool, keeping a weekly eye on the heft around the rib cage is as vital in checking whether you aren't overfeeding, a trap into which doting or anxious owners can easily fall.
Please be aware that pet piggies tend to be a bit heavier on average than breeder piggies (on which the literature is based). There is nothing wrong with making the best of a good diet and a wide range of nutrients combined with plenty of regular exercise/run time as long as it doesn't result in your piggies ending up overweight.
You can find more information about weight and how you check the heft in this guide here:
The Importance Of Weighing - Ideal Weight / Overweight / Underweight
PS: Here is a picture of Helygen and her husboar Pioden. They are my smalled and my largest piggies. Pioden is double the size and weight of Helygen. They are both healthy adults with a perfect heft. Helygen is just about touching 700g while Pioden is around 1400g. Nothing wrong with either - it is just the way they were born. Pioden is covering my whole lower arm when I pick him up, but he hasn't got an ounce of extra weight on his massive frame. He could easily be 1600-1700g without being massively overweight. But it is tiny Helygen who is bossing him around, by the way!