Needs lots of help so confused

A have a 16 week old piggy called cocos nd just got a 4 week old piggy teddy they lived seperatly for 2days due to the fact teddy is tiny. But i introduced them on neutural grounds. There was a bit of humping but nothing serious nd it died off after 15mins a no it was just cocos being dominaint. I seperated them after an hour but they were sqealling for each other. So i put them in the same cage while a made up the pen so they hav more room. Ive put a bridge over the joint for access to the pen cocos can get across no bother but teddy cant he just hides under it. Everything seems fine they eat next to each other sit together nd everything. But cocos has started to rumble at teddy nd follows him around the cage nothing comes of it as coco runs off. A just dont no if this is normal as ive only had teddy 3days