if you are referring to the diet portion...at this time of year not a problem..spring is more of a concern because of the early grass growth. If you are talking about safety..if she is alone..personally I wouldn't do it. If she is with other horses then any time at this point. I hate night turn out just because the horses feel more vulnerable at night so behavior can change but many, many people have horses out without a problem. the only time I have ever had a horse get hurt was at night turnout because of daytime heat concerns.
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