I always worry about the texture of the eggs, like if they are soft enough for the babies to slit... But I'm always worried about everything! LOL
I'm pretty sure that at day 52 it's real safe to cut, but I know it all depends on temps...
*Someone please correct me if I'm wrong*
I had 3 out of 6 pip last week on day 52... so I slit the last 3. I just gently pinched the top of the egg to make a fold, and made a tiny cut with cuticle scissors on the fold... that was it! I'm sure everything will work out great! BREATHE!!