just made [well a friend has] a whelping box who has put pig rails all around do i need them in the front? this is her first litter so i don,t know how she,ll be

I would use them all round as your bitch may decide to sleep in the front - better to have 4 I say ;)

Far better to be safe than sorry. Suggest you add a rail to the front.

Put them in.  They only cost a few pounds and it is better safe than sorry.  I only left mine in for a couple of days and took them out once I had observed my bitch and her litter closely.