My hedgehogs keep leaving poos in there too! yesterday there was a healthy looking one, and today another healthy one, I presume black and hard is healthy?
But a week ago I saw a softer brown poo, and when I first starting feeding them (just hedgehog biscuits, no wet food or cat biscuits) and fresh water – I saw a little patch of very wet brown poo.
I don’t know why, but I guess if we keep feeding them spikes, and dog food in jelly, I think it will be okay – as that is what hedgehog rescue centres probably use.
Maybe if it continues, you could ring BPHS – for now perhaps just monitor it.