If the water eggs were registered with the ore dictionary as itemAnywater then they could be used in recipes that require water buckets without first having to place the water, scoop it with a bucket, and then craft one at a time.

That's a pretty simple fix @BaronMalkar. as far as @IamAlathe depends on what version your on ,because I think that has to do with the fluid registry stuff.

Fluid registry is on it's way out. If you are still using that code in the new versions that would explain why they are not working with some tanks.

not fluid registry.. capabilities. I still just use old terminology.

Lava eggs have the same issue of needing to be placed in the world. I nearly killed myself trying to put one in my Tinkers smeltry tank. That seems like it would be a pretty simple fix for the fluid eggs. I admit I could be very wrong, since I know nothing about coding or making these mods.

I know it's Minecraft 1.12.2 I had that issue on, and it's probably been a couple of weeks ago now. I'll try to remember to check it out when I get home and get you more info. At the time I had the most recent version of Chickens, More Chickens, Hatchery, etc. I know that's less helpful.

possibly fixed by #124

I've just spent some time doing some testing. I've never used industrialcraft, so I did not do any experimentation with that mod. I was unable to use the lava or water eggs to do anything other than place a lava or water source block in the world. I could not fill tanks or barrels, they did not work as a lava bucket in a stirling generator, or a water bucket in combustion generator. All versions are the most recent available on the Curse/Twitch launcher as of this date. JEI, Waila, and Hwyla are my basics in testing. I added ceramics (which has a barrel), Ender IO, and tinker's to experiment with these fluid eggs. In all my experiments, I was able to use water bucket, lava bucket, or both normally. Lava and Water eggs either placed a source block in the world, or did nothing/was not usable.

Minecraft: 1.12.2
Forge Version: 14.23.4.2707
Chickens Version: 6.0.4

Mod List:
Ceramics
Chickens
Ender IO
Ender Core
Hatchery
Hwyla
JEI
Mantle
More Chickens
Tinker's Construct
Waila

Just realized I didn't try basic crafting. With my installed mods for this test, the only thing craftable with water bucket is feather pulp (I couldn't see anything for lava bucket). Crafted successfully with water bucket. Could not craft with water egg.