May not fit your problem with Splay Legs, but I had NONE after giving my breeding pens (trios) hand fed Cod Liver Oil sandwiches. Spread about 2 1/2 T CLOil on a slice of 9 grain bread. Place another slice of bread on top. Hand feed each pen, one fourth of the Sandwich. Hang on tight or first one will take it all! AT least 3 X a week during collection of hatching eggs...Our Lay Feed has no animal products in it any more. Vitamins A&D may be minimal, and fade with storage of feed. Splay chicks have hip joint bone not finished at hatch. Will just finish and harden in a day or 2--splayed and no recovery, if legs are not held in normal position (Band Aides) and can be given a drop of Cod Liver Oil by eyedropper (top of the mouth, so not to choke). Several days of Cod Liver Oil, and the band aide support can be removed and perfect "finish" for the bones. (sometimes a 2nd support time may be needed.) Had a series of pictures, sorry I cannot post them any longer. No, not the end all to the problem, but was completely successful for my Bantam hatching for many years. I blamed the egg, not the incubation. And the hen fixed the eggs!