The "Castrated" (is_castrated) boolean attribute on Animal assets is intended to be used to denote animals as sterile or not, but it's current name is limiting because it is too specifically about "castration".
This has been discussed in community calls and a proposed resolution is to rename it to "Sterile" (is_sterile).
This would be a breaking change, so it cannot happen in 3.x, but can be part of the 4.x roadmap.
"Castrated" becomes "Sterile" on Animal assets.
The is_castrated attribute becomes is_sterile on Animal assets.
(Same as API changes.)
Active
3.0
Farm Animals
I sketched up a 4.x-is_sterile branch for this. I will open a PR on GitHub when we have a working 4.x branch to test against. Postponing until then.
PR is ready for review: https://github.com/farmOS/farmOS/pull/960