chicks

[marias]

a recent hatch of five chickens - four had splayed feet and died. does anyone know why this should happen - what is the cause

[wildwood]

Most probably rickets.

If the eggs came from one hen she most probably is unable to utilise the calcium you provide for her.
If the eggs came from more hens you need to provide a calcium supply for the hens, something like oystergrit or similar.