I wonder if anyone else has a problem with the plastic inserts of the whelping mats.   I bought some 4 years ago, and the inserts have gone extremely  brittle  and are splitting in very sharp dangerous shards.      

Not exactly heavily used - for the first fortnight only, on one litter a year for the last 4 years.

The company who made them don't want to accept responsibility for them, but will sell me some more - not exactly good customer service.......

Jo

I used them for a couple of litters. Thought they were good but a pain to get into the mattress.
They have now been abandoned to make the walls for the first few weeks in my freedom pen.
Funnily enough I have poked holes through for wire ties and they have not split so sounds like you have been unlucky.

Get some. Perspex or plywood cut to size.

Just about to do just that.    The company were so unhelpful....

Jo