L.S.
They are probably teething. Are their gums swollen? My son teethed from 4 months on (off and on). Try a little tylenol for one night and see if it helps. Just make sure you follow the infant dosing and use infant tylenol. Also, make sure you are feeding baby enought at night. They may be going through a growth spurt and need more calories. Try extra formula or feeding at 11 pm. They may help them sleep longer. Also, sometimes babies just cry out in the middle of the night and then go back to sleep. Try putting one in another room so they don't wake each other up. It is fine for them to sleep in your room but it makes for restless nights. I co-slept until 10 months and realized that I could have made the switch much sooner to a crib! Little cries in the middle of the night are normal for young babies. Separate them if you have to. Just layer the clothes and they should be warm enough babies have that extra layer of babyfat to keep their temp more regulated.