Definitely Leghorns have these issues. Anecdotally, I’ve only had two… a Brown Leghorn and a California White, which is 3/4 Leghorn and 1/4 Plymouth Barred Rock. The Brown Leghorn (Margo) died of a chronic egg yolk peritonitis infection that went septic. She also showed a background Marek’s infection, which likely compromised her immune system per UC Davis necropsy write up. She showed signs of a reproductive infection about a year before her death, but never had soft eggs and laid frequently.
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The California White, Dorothy, battled soft eggs on and off for about a year. She slowly got less active over time, but seemed mostly healthy (except for the soft eggs, which made her feel lousy and were exhausting to pass). Until, suddenly one morning she seemed miserable and was hiding. She had the same too-deep-of-a-red colored comb Margo had before she died. Poor Dorothy died that evening.
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Because of the timing of her death, I was unable to send her for necropsy. She is buried under the giant walnut tree you can see hovering over the run in the background.