Glad you put them together. I was going to suggest that. The more mobile one will encourage and stimulate the other to get his legs going! "Keep up, buddy!"
Congrats on the hatch! :clap
Orpingtons are little fatties! :D I usually have one or two each hatch that take a couple days to get upright. As long as the feet stay out front, it should be fine. Just watch that they don't spraddle and need banded.
And are the 2 that hatched still in the...