Young ones in general

[The Skarzs]

  So, we all know the Dibbuns, their antics and adventures, but some things aren't explained.
  For example, why are most of the young ones so rambunctious and mischievous? Real children aren't always that troublesome; sure, they all have their moments, but from the books there's always those Dibbuns who are ridiculously defiant and troublesome. (Of course, there's not much in the way of parents to guide them, apparently, and they all just scramble around in a group waiting for the badgermum or abbeybeast to attend them.)
  A different note is: In Redwall, are the babies born pink and. . . undeveloped like real life rodents, or are they slightly furred at least? It is quite apparent that they aren't born in such large numbers as real mice or rats, so it's not inconceivable that there be other differences as well.

[Hickory]

I was actually going to make a long post about Rollo and examining him and his Dibbu-ish antics that shows how Jaques changed Redwall, but this topic's fine.

While they don't show an actual birth in the series (I think) they only ever describe the really young days of the Dibbuns as "nursing them" or something along those lines, which is pretty vague. Jacques seemed to model the DIbbuns development along that of a human baby (intelligence before physique) instead of the other way around, as it is for real-life animals. It was really just a matter of creative license and however he needed the scene/character to play out. 

[Jukka the Sling]

I hate the idea of the animals being born pink and furless.   And anyway, I don't think they were.  In TLoL, one of the illustrations of a very young Martin shows him with fur.

And yeah, you're right, there seems to be a lot of random and unsupervised Dibbuns running around.  Their parents aren't often mentioned; it's almost as if they're orphans.  Then again, with the communal Abbey life, maybe everyone sort of helps raise them.

I can't explain why they're all so troublesome.  Maybe it's a lack of discipline because, as I said, everyone sort of looks after them but aren't entirely responsible for them.

[The Skarzs]

Mattimeo was probably the best book in regards to young ones; it showed the parents, who cared for them, even if that meaner correcting them, the devotion of the one to the other, the real orphan, and the different personalities.