Too Much Weight Gain?

I adopted my chinchilla from a shelter on December 21st 2014. I've weighed her frequently since then and in 45 days she's went from 627 grams to 742 grams (115 gram gain) and still seems to be gaining. Her weight according to her adoption paper was 660 grams. (My scale was low on batteries and I've since changed them so if we go by her weight on her papers to now it's an 82 gram gain if my scale was off at the beginning. I'm not sure.)

My question is, is this much weight gain normal? Is it too much? Should I restrict her pellet food to two tablespoons day with unlimited hay?

I'm hoping she is not pregnant. It has been 116 days since she was brought to the shelter. She was there for two months. There was one other chinchilla separate from her in another cage that I was initially told was male and later told was female. I don't know if they had any contact. I cannot feel any nipples or see any movement of kits.

Unless you are feeding cheap and/or treat filled food or giving treats daily and the chin isn't noticeably getting chunky (they can get little fat rolls most noticeably under their arms) I wouldn't cut down on food. It could just be the chin was underweight to begin with and with a better quality food it's put on weight. Also I noticed with my two boys that they actually gained weight when I switched to the flying saucer wheel, they use it all the time and I can actually feel they put on muscle. Though they did each gain just under 100 grams they did so over about 6 months. You do want to make sure you weigh her at the same time every time too, whether she just ate, drank, pooped or peed, or not will effect weight.

Unfortunately with chins sometimes you can't tell they are pregnant until they pop out kits, however normal gestation is 111 days. Since you said that there is another chin there (possibly male) I would just count 111 days from when YOU got her to make sure she isn't pregnant. It does happen that people make mistakes and put chins back in wrong cages and breeding only takes a second, and it can also happen if the cages are too close together.

Thanks! I guess I will just have to keep watching for the next 66ish days.

I'm not sure what food she was on before as it was just labeled Chinny Chow but I switched her over to Oxbow. Tilly seems to be eating all the time but she doesn't appear to be overweight yet. She does get pinches of organic rosehips, organic oats, and I also use a bit of lifeline to supplement here and there. I will try to limit this more. She used to use her Chin Spin frequently (all night long) and now she only does once in a while so that might have something to do with it too.

Just in case, I would remove the wheel until you are sure she is not pregnant or until the babies have been weaned. If you keep any babies, wait until they are 6 months old o give it back.