Those pots are too small, get ones at least 8" wide x 8" tall. The one on the right is probably root-bound and not getting enough water and oxygen, I agree with plenty of drainage holes.

Yellow leaves that fall off means the plant is getting too much water.

Yellow leaves with burnt tips means not enough water.

I have all of my minis in 13x14" pots and I'm wondering if some of them are in too small a pot because they've filled it up rapidly. They all sit on cedar stands my husband made to get them off the ground by about 3 ". If your drain holes are on the bottom of the pots and they are sitting on the ground then they still can't drain.

Both of those pots have drainage holes, Beth. I constantly move my pots. Whether it be an inch or a whole foot, drainage is not an issue. And cleangeek, I just transferred both of those plants into bigger pots. And the pots they sit in now, are the bigger ones. I had like 2" small plastic container (which is what both of them came into), I transferred them into two 6" pots with drainage holes. The owl pot, is just like a container you stick a pot in? If that makes sense..

Are they getting enough sunlight?

That's what I am wondering.. I'm not sure, cleangeek. The thing is - I put them in sunlight, and the one in the left (owl pot) if you look closely enough - the stems look burnt? Which made me pull this mini rose inside and I placed it into a window seal yesterday.

They should be outside. Put them in a sheltered part shade location for a few days until they are hardened off and then full sun always after that. Water deeply when soil is dry. Don't over water. Good luck.

They need MUCH bigger pots! Get some larger pots with lots of drainage holes in them. Do not put them into other pots like the owl pot. I have that same owl pot by the way, lol! But I don't use it for roses at all because it's too small and doesn't have any holes in it. Also, don't put any trays under the pots. They have to be able to drain freely so the rose roots don't sit in water. They do not like that at all. That is one of the main causes of leaves yellowing and falling off. The other, unfortunately, is not enough water! It's a vicious circle, lol.

Re-pot them with good potting soil, put them in full sun and do not fertilize them until they begin to get new growth on them. Then just do the fertilizer at half strength. You don't want to burn the roots.