My friend owns a IRN Paulie, and since she got him he has been doing mostly watery poos, she feeds him a bit of everything but mostly celery, carrot and apple. My IRN is Tango and we got them together and his poo is quite normal looking. Tango also eats celery, carrot and apple as well. Does anyone know what can cause this? Paulie appears absolutely healthy it is just his poo that is a little concerning for my friend

Thanks,
Jo and Tango xo