How long should you handle a 7 week guinea pig for at a time? my two have got completely different tempermants..cookie is laid back and will sit for ages on your lap being stroked..but cotton ball.. after a few minutes will start to get very restless and try to nibble anything she can get her hands on including trying to get my finger sometimes...Why does she do this? Does she just want to go back into her cage do you think?...is it normal for babys to nibble I did read somewhere that it was..