My three female rats are all three months old. They are scatter fed 1/4 cup of oxbow (split up into a morning and night feeding). I also provide some chopped up veggies and fruit (depending on what we eat it can be: greens, carrots, peas, blueberries, cranberries, turnip, squash, zuchinni... Etc). I've avoided higher sugar fresh foods like corn, sweet potato, or melons. Even the berries I'm sparse with, usually no more than one or two berries for each rat. When I wake up in the morning around five in the morning they are out of food. This is the time I free range them and play with them... This also serves as a fasting period. Around ten in the morning I grab a tea spoon of unsugared grain (rolled oats, barley, or kasha) for treats and training. Then I provide them with their morning oxbow. I never feed dairy, meat, or eggs. I feel like they are on a super strict diet... As well as they have lots of stimulation- scatter feeding, hanging toys, hammocks they need to climb for, hours of free range, two wheels, I work from home so almost constant companionship... All three have good coats and have energy but Peaches keeps on putting on weight... She looks like a little pear next to the other two. I've been watching at feeding times and the smallest rat and Peaches get really excited and appear to eat similar amounts... The medium sized one can take or leave food it seems. It is also funny because Peaches really isn't treat motivated for tricks, and usually will accept a treat but then cast it aside in favour of attention as a reward... I don't know how she's putting it on. I've owned them longer than a month, so I know she isn't preggers. And we were went the vet two weeks ago and he said they were all healthy females. I am truly at a loss... Should I be worried? Is it normal for young rats to put on a little weight in adolescence? Could she just be a little more curvy than the other two?