There is only one Australian brand of pellet that I would class as good, the other two good ones are from overseas. Vetafarm is a good quality Australian brand, available from most pet stores and online. Oxbow is a very good brand from the USA, you can buy it from selected vet clinics, if you look at the Oxbow Australia website it has a list of clinics that stock Oxbow products and just ring the one closest to you. If they don’t have it in stock they will usually order it. I have seen Oxbow in a single pet store, you can also order it online. Burgess Excel is from the UK, it’s also a very good brand, and the most expensive of the three. Pet Barn stocks it and you can buy it online as well. Online sites are My Pet Warehouse, Pet Barn and Guinea Pigs Australia.
Another important reason for phasing out the pellets with the mix, is that corn doesn’t actually digest well and is well known for causing blockages in rabbits. The excess cecals could also be from the hay that you are feeding. If you are feeding a different hay to the breeder that is a bit more rich, it can cause excess cecals. Once when I got a new bale of hay for Bandit, it was very fresh, just cut the day before and very green. For a few days after having that new hay he had excess cecals but he adjusted with time. Sometimes young rabbits also seem like they produce a lot because they simply don’t eat them, so that may be the case too that she’s simply not eating them when she’s supposed to be. She’s still pooping formed poops and eating well so I don’t think you need to worry about a vet visit at this stage. Young rabbits just have more sensitive guts.
In regards to the saw dust as bedding, it’s not a good choice. You can use kiln dried pine shavings, but they MUST be kiln dried. Do you have a litter tray for her? Many people only use bedding or litter in a litter tray. I use wood pellets, Oz Pet brand but there’s a couple of others that I can’t remember the name of. You can also used pelleted recycled newspaper, Back 2 Nature or Breeder’s Choice. If you want to have bedding in the rest of the cage you can use straw or hay as bedding as well, you can also use fleece blankets providing she doesn’t chew heavily on them. A little nibble here and there is ok, but if it’s a lot of chewing and ingesting you must take it away, don’t use towels or other similar items because the long fibers can cause gut problems.
Also, generally rabbits do pee a lot, they’re eating very dry food all day so drink a lot of water, and it has to go somewhere!
Hope that helps