Splayed legs- The make-up sponge method.

You may see the first signs of chicks being splay leg 5-6 days old. It will show dark/red discolouration at the knee joint. Followed by discolouration at the knee and hip joint. Also the chick will lay flat on its tummy and be underdeveloped. Most of us will notice a splay leg chick at time of ringing 7-11 days old. The earlier its fixed the better. Under 21 days is best for this method. 
What you'll need: Make-up sponge, 2x tubes (I use four pens) or thin card rolled 5-6mm diameter, scissors.

  Use the flat rectangular sponge. Cut in half. 

Mark 2 spots, approx half inch apart.

  Cut a tiny hole in the sponge. Then push tubes through. 

Push the tubes as far to the edge of the sponge as you can and trim excess.

 Put chicks leg (1 at a time is easier) in tube, over 'knee' , and gently hold sponge in place with one hand and remove tube with the other hand. Repeat for other leg.

The chick can still get around the nestbox with this on. Leave the sponge on for 7-10 days. Add calcivet to the water. The sponge can very easily be torn off.