I have 2 baby boars, both born on March 7th, and another 4-6 month old male with them. All of them are exceedingly small, especially the older boar. He's around maybe 5 inches long, and I was told he was 6 months old when I got him (he obviously isn't). I've seen 3 week old guinea pigs larger than the babies, so I'm quite concerned about their health as of now. What can I do to make sure they mature to full size? The only other small male I have I got last August, but at the time, he was given to me when he was a day old, which makes sense as to how small he is. However, the baby males were with their mother up until 3 weeks old, so I still don't know why they're so small. Help?
Hi and welcome
The size is genetically determined but bad breeding/neglect can impact on that further. Unless they carry an inherited genetic fault due to bad/uncontrolled breeding, small size is not a problem. Small babies often grow more slowly and the gap in weight can rather widen during their lifetime. This is not a problem as such as long as their genetic inheritance is fine.
Body size and weight on their own can't tell you anything about whether your piggies are fine as they are or not. In addition to weighing weekly (or daily at the same time during an illness), you need to establish first whether they are a normal weight for their individual size or not. You do this by feeling around the ribcage. Our weighing guide tells you exactly how to do this. Normal cheap kitchen scales will do the trick.
The crucial point is not whether your piggies are undersize but that they are healthy and a good/size weight ratio in themselves at any point of life. It doesn't matter whether they fall into the 50% band of 'average' weight or not because that is an arbitrary human definition, which excludes a full half of perfectly healthy guinea pigs with a perfectly normal life expectancy as being 'wrong'.
I've had piggies living to 8 years old that were feeling overweight at 800g and a boar who was bordering underweight at 1500g. In fact, my currently remaining old lady was just 40g when born (which is pretty much the bottom end of survivable birth weights; the largest babies can be three times their size at birth) and needed a helping hand in her first days but even though she always has been smaller than her two 'normal' litter sisters, she has outlived both.
Please take the time to read up on our weight guide link. The weekly weigh-in and body check is your most important tool for regular health checks and spotting a developing problem early on and being able to manage your feeding care during illness and recovery poperly. Establish first which generall ball park your boys are playing in (normal heft/BMI; overweight or underweight); then you monitor their weekly weight from there.
Here are the links again:
Weight - Monitoring and Management
How To Pick Up And Weigh Your Guinea Pigs Safely
The biggest health boosting and life prolonging factor is a good hay based (and NOT veg/fruit or pellet) based diet. if you start overfeeding your piggies in an attempt to boost their growth and getting them into the 'normal' range, you will do that at the cost of shortening their life span that little bit more. The more their diet resembles the one guinea pigs have evolved on as a species, the longer your piggies will be able to live a healthy life span (barring any unforesseable medical issues). In my own experience, the difference can make around 1-3 years and take any healthy piggies from the lower to upper end of the average life span or even a bit beyond.
Your piggies will also realise their genetically determined optimal weight and size on their own in their own time on a good normal diet. If you overfeed now, they will end their fast growth phase simply sooner as soon as they have reached a certain percentage in their genetically determined weight/size ratio. From then on in, overfeeding will start going towards yellow fat reserves.
Here is our diet guide, which looks at diet as a whole but also at all food groups in detail. It is your biggest 'gun' for giving your piggies a healthy and long life:
Long Term Balanced General And Special Needs Guinea Pig Diets
Here is our new Owners' guide collection with lots of other practical how to tips and important step by step information to help you for a good start to a hopefully long and happy life:
Getting Started - Essential Information for New Owners
Whatever you do, always aim at quality and not quantity. You cannot change any genetic inheritance but the quality of your diet will boost what they have and give them extra days in a very happy life - and it is the happy days that guinea pigs measure their own life by. They don't have a concept for 'average', whether that is size or life span; but they know when they have a good life for sure!
Enrichment Ideas for Guinea Pigs
