How do pigs compare giving birth in the field vs pigs giving birth in farrowing crates?

After a two years of keeping the grower pigs in cages, I decided to release them onto a total of 6 hectares ( 14 Acres ) of land to graze on. I made two camps of 3 hectares.

I kept the sows in an open area close to the cages, so that they can still sleep there at night.
This area is closed of with fences and is about 120m2.

Once they got used to this system, I let the pregnant sows out of the camped area and let them farrow on the land. This was scary at first, as I did not have experience of sows farrowing outside and was afraid that they might lay on top of the new born piglets.

No piglets were lost as a result and last night's pigs were born in 4 degrees Celsius.
The mother's sow also looks a lot more at ease and the work is less intensive on my part.
Please watch: https://youtu.be/e-UTEH4T_8s

With this picture you can see how the pig made a good nest that protects her and the pigs from the wind and sun.