Guinea pig losing hair

[Nicola roberts]

Hi can someone help plz.....my nieces guinea pig has a big bold patch (doesnt look sore or scratched or irritated) its a male guinea pig that lives with another male no signs of fighting.or anything.....what could it be TIA

 

[Wheekallweek]

It could be many things, from a fungal infection to mites to something else completely. The only way to tell for sure is to take piggy to a vet!