Sounds ok to me, a mixture is always best for them IMO.
Can you get some Bermuda grass- will it grow in your region?
According to online sources I've read info that Bermuda supposedly is their natural diet.. that Bermuda didn't actually come from Bermuda, it came from Africa.
Is that true? I'm not sure...
Still a mixture of different types of grasses & weeds is best.
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PHRatz