What is the appropriate method to send a strain?
I believe Addgene send strains as bacterial stabs.

This is the protocol from Qiagen.


  E. coli strains can also be stored for up to 1 year as stabs in soft
  agar. Stab cultures are used to transport or send bacterial strains to
  other labs. Prepare stab cultures as follows:
  
  
  Prepare and autoclave LB agar (standard LB medium containing 0.7% agar) as described in the last issue of QIAGEN News (1).
  Cool the LB agar to below 50°C (when you can hold it comfortably) and add the appropriate antibiotic(s). While the agar is still liquid,
  add 1 ml agar to a 2-ml screw-cap vial under sterile conditions, then
  leave to solidify.
  
  
  Vials of agar can be prepared in batches and stored at room
  temperature until required.
  
  
  Using a sterile straight wire, pick a single colony from a freshly streaked plate and stab it deep down into the soft agar several times
  (Figure 1).
  
  
  ￼￼￼￼￼￼￼￼￼4. Incubate the vial at 37°C for 8–12 h leaving the cap
  slightly loose.
  
  
  Seal the vial tightly and store in the dark, preferably at 4°C.
  
  
  When recovering a stored strain, it is advisable to check the
  antibiotic markers by streaking the strain onto a selective plate.


I believe if the shipping is &lt;24hrs you could send a stab in ice.

Hope that helps

Ben