@Arduska

They need to be first -

1. Active/in your house (inside or yard)
2. Not on a hoard and fully rested (aka available to go on another hoard)

Then if you view their overview page, where you'd send them on hoard, there is a button that says "Trigger Evolution". If they've reached the minimum level, you should be able to select the evo bar for them to eat. :)

I had to wait until one of my pets was done resting, but here is a screenshot in case you can't find it!

Oh thank goodness, thought I was doing something wrong. lol Glad I looked in forums, thank you.