New Guinea Pig

Question
I got a guinea pig, Hamilton, on Saturday of last week (October 1st). I have had cavies before and know that they should be in habitats with one or more other guinea pigs. Knowing this, I got another guinea pig last night, Guinness. I introduced him to the environment, and initially he ran straight towards Hamilton as if he wanted some sort of comfort. Hamilton eventually humped him to show dominance. Guinness is very docile, and will sit one my lap for long periods of time without moving. I have not seen him eat much. He went to the food dish and Hamilton scared him away. This has happened at least twice that I know of. I removed Hamilton from the cage after I saw this to allow Guinness time to eat. I have even made a plate of carrot and pellets for him to eat on his own on my bed. He only ate a small amount of food. He chewed on a wooden chew toy a little. He seems to be grinding his teeth, as well. His feces seems normal, and I think that he has been drinking fine. Is my new guinea pig okay? I'm really worried. Hamilton eats almost constantly and moves around a lot, which is a stark contrast to the behaviors of Guinness. Any insight would be greatly appreciated. Thank you.

Answer
It generally takes a little time and patience to introduce a new pig.  I'd like to bring your attention to something regarding new pigs in the home. That's a quarantine period. Before you bring a new buddy into the cage you should keep him isolated away from your other pig. That's just to be sure he isn't carrying some virus into your home, and to protect the other pig.

It doesn't sound to me as though the new pig has anything serious, so I think all he needs is time.  Hamilton is just showing a territorial behavior to let the new guy know that he's got to show him respect.

As for the eating, give Guinness time to adjust. That usually takes at least a week. Just be patient for awhile and let him get used to his new surroundings. Then he should be fine.