How often she poops may vary. It could be more than once a day or skip a day, but usually every day. As their system get bigger they don't necessarily need to poop as many times a day. The amount of poop will increase though when they do poop as they get bigger.
You may want to try slowly extending the night feedings to every four hours, then five, then six over the next few days. If she does well with four hours for a night or two, you could try five hours. Bear in mind that she may drink more milk at each feeding, and that a growth spurt may alter her needs too. You don't want her frantic for the bottle. But she may be ready to lengthen the time between feedings and she may not. You'll have to experiment.
You may want to try slowly extending the night feedings to every four hours, then five, then six over the next few days. If she does well with four hours for a night or two, you could try five hours. Bear in mind that she may drink more milk at each feeding, and that a growth spurt may alter her needs too. You don't want her frantic for the bottle. But she may be ready to lengthen the time between feedings and she may not. You'll have to experiment.