jack russell coat getting thin since neutering

by Deirdre
(Irelanf)

My 4yr Jack Russell was neutered in June but I have noticed that in the last month his coat has started to get very light on his tummy, legs and neck. You can see his black spots on his skin the hair is so light, he's also shedding like mad. I'm telling myself that this is all down to hormonal changes since being neutered. Is this a normal occurrence?