Kaneke, good to hear from another island chickaholic. I live on the westside of Kauai, been raising RIR chickens for the last 10 years or so. I just got into hatching my own chicks this last year. I too had difficulty finding a water wiggler and other supplies here on Kauai, though did find most of it on Oahu. My DD goes to UH so I'm always having her buy and mail me things.
My latest thing has been trying to find different breeds of chickens to hatch. I have shipped eggs a couple times, but not with good results. They take a real beating and a couple extra days to get over here. All my hatches have been in the 20-30% range with mailed eggs where my personal eggs I can get 80+% to hatch.
I have relented to finding local sources for good hatching eggs. I was able to find some barred rocks eggs when I was visiting Big Island, got them in the bator right now, 10 out of 12 hand carried on the plane are making it so far on day 17. I have RIR and wanted the barred rocks so my eggs will be sex linked chickes.
I read about guy on Maui that had RIR, barred rocks and delaware chickens. He used them to make red and black sex link chicks for sale over there. Might keep your ear to the coconut wireless to see if you can locate him.
On Oahu the Wailua feedstore on the north shore used to carry baby chicks and poultry supplies, but I haven't been there for several years.
I know what you are saying about shipping over here. Forget about FedEX and UPS they are $$$$$$$. Best deals I've found if to use the flat rate boxes. Many time I've had things that I buy that have free shipping to the 48 states. I get it shipped free to a friend on the mainland, they stuff it into a $9 flat rate box and it get over to me. UPS would want $40 to ship the same thing.
Give me a shout out if you need any local knowledge or help and I'll see what I can do,
Aloha,
Cory