The last few nights DS has been waking about 2 hours after he goes to sleep.. screaming because his leg is stuck between the crib bars. Just wondering the age a LO makes the transition to a "big boy bed" or if there is anything I can do to try to prevent this from happening. I'm worried he will be sleeping with his leg stuck and will try to move onto his side or something and will get hurt. Any suggestions would be great. Thanks!