I think it has something to do with calcium absorption- not sure, they don
t like it anyway as I have citrus trees around and they ignore the fruits and leaves.
Mine won't eat citrus anyway. I frequently raid the compost bucket for chickie treats and occasionally end up with a grapefruit peel in the henpen, they profoundly ignore it....
hmm...and i have been giving mine bad oranges for a wile now. Just one sliced up every now and then. They ignore the rind and go for the flesh
Seedless oranges
Mine have been eating citrus for years with no bad results. Mine love the grapefruit that falls to the ground, and the meyer lemons. When we had orange trees, they would eat ornges as well--which is more than I can say for us, becuase we wouldn't (they were not very good--one tree's fruit was always nearly bone dry and the other one was not very sweet)..
I live in Florida as well and have citrus trees. My girls like an orange occasionally but seem not to prefer them as regular treats. They don't like grapefruit at all. If they want it, they eat it; if they don't it goes in the compost pile.