Hi Eddie!
Welcome to the Wonderful World of Chinchillas! And to the Chinchilla Club Forum.
Totoro lost her mother at about 3 weeks old but she grew up just fine. ... Totoro is a week older than Kiwi (roughly 7 weeks old). ... Totoro is eating more than Kiwi. ... Totoro appares more dominant. ...
Each chinchilla has it's own special personality ... no two are exactly alike. Due to the fact Totoro was abruptly weened at a very early age (because of the death of her mom), she has been eating solids longer and did not have mom's milk as long. This could affect most chins in two totally different ways (1) They give up and or become timid. OR (2) They become a survivor and develop a more dominate personality. Totoro seems to be #2. This is good for survival, but can be a little ruff on the cage mate. As long as they are not fighting, they should be OK ... They can play fight and have little scuffles and that is OK ... BUT ... should there be a real fight (bites that break the skin), they would have to be separated and live separately. Totoro probably has larger poops because her system was more or less forced to develop earlier due to the mother's death. By taking the stance of sitting next to the feeder when eating and occasionally mounting Kiwi, she is probably the dominate one and will more than likely continue to be the alpha chin.
Kiwi being the younger (6 weeks old) ... Kiwi will stand up to grab pellet for herself, Totoro will "bark" at Kiwi once. ... Kiwi's poop smaller in size. ... Kiwi's stools are smaller in size but it is firm, dark and does not smell. ...
Personally, I do not let my kits leave until they are 7 or 8 weeks old. I like to ween them at 6 weeks and watch them for an additional week to make sure they are doing OK on solids and away from mom. Kiwi's system is probably trying to adjust to all solids and no more of mom's milk as well as being away from her mom and brother. This usually tends to make a chin more timid. As long as her poops are firm, moist and do not smell, I think she should be OK. You might want to consider adding a bottle of goat's milk to the cage to help her physical system adjust. She is also having to adjust emotionally ... the goat's milk is a little comforting for her also. (It's good for both of them.)
As far as the restrictions on the food Totoro is giving Kiwi ... you might want to make sure there is always food available at all times and even consider a second feeder.
Animals will fight over food, second only to fighting for the protection of their kits. The less stress you can make between the two (by adding a second feeder), the better it is for Kiwi's development and for the future good will towards each other.
Jo Ann
Keep us posted on changes made to the living area and the reactions of Totoro and Kiwi to them, please.
I see cadillataste was answering the same time as I ... we agree, too.