Nature tends to mop up the injured and lame fairly quickly - it is red in tooth and claw, after all. However, a bird's bill is a bit like a fingernail in that it keeps on growing. Toucans in captivity do sometimes break their bills due to fighting or collision or as a result of vitamin imbalances. There are ways of mending them and experiments have been done using various glues. A toucan's beak is quite slow-growing so natural repair can take a long time.

I don't like to see animals kept in cramped conditions either, but I'm guessing that these toucans will have a better chance of surviving than they would in the wild - if only because they'll be fed and protected from predators. Older toucans can also display overlapping areas of growth on the beak - is it possible these look like cracks?

An interesting digression: birds sometimes have long curly appendages to their bills where the normal wear-and-tear has somehow stopped temporarily. See this page for a photo:

http://www.dailymail.co.uk/news/article-445324/Why-Freaky-Beaky-feeling-peaky.html

This can be caused by a chip in the lower mandible that allows the upper mandible to over-extend. The upper mandible isn't getting worn down in the normal way so just keeps getting longer. It can happen to either or both mandibles.

Incidentally, if you have a keen interest in birds, you might consider taking part in the scientific surveys conducted by the BTO.