Pigs Roll Over for Belly Rubs

I like having happy and friendly pigs. 3 out of the 4 roll over to get their tummies rubbed. These boys push up against me really hard before going down on their side. After they get their time from me, they do relax and walk around more, but not until they get their attention time in. (I have had previous pigs roll over for belly rubs in the past years and those didn't almost push me over like this year's boys.)