I recently bought 2 sister guinea pigs. The lady who sold them to me said that the were eating fine and were really healthy. I got them home, they won't eat pellets or veg, cower in their house or a corner all the time. I know they are older then she told me, and she kept them in a really small cage. What do I do to make them more comfortable in the larger cage? And how to I get then to eat pellets or veg?