Hello,
I am not an expert on giant day geckos, I have only owned mine for 2 months now, and she is a great pet. I do have a book on day geckos titled "The General Care and Mantenance of Day Geckos" and it does have a specific section on phelsuma madagascariensis grandis. I can give quotes from the book that seem to answer the questions, I'm sure an experienced breeder would be able to provide better information, but this may be of at least a little help.
1. What are the best conditions as far as enviroment is concerned to privilege breeding.
"Horizontal bamboo strips are useful for basking. Additionally, vertical bamboo stalks at lest 2 in. (5 cm) in diameter, and partially hollow at the top, are useful for the female to retreat into when laying her eggs.
2. At what age should they be able to do so?
"Generally, a female should not be used for breeding unless she is at least a year old."
3. I think I have two male and one female...should that do it?
"If you want to breed them, house a male and a female together throughout the year... If a female does not show proper courtship behavior, she may be attacked by the male. Compatibility of specimens is essential... The pair, if compatible, should not be separated, as separation may lead to future aggression."
They always been in the same container.
"With this taxon, it is best to raise each of the young separately in small vivaria." And from my personal experience I would suggest that you do separate the three of them. Typically with geckos males will fight eachother if housed together, I'm not sure if this applies to madagascariensis grandis, but I would assume that it does. Also, my madagascariensis grandis was given to me as a gift from a friend because she was housing all of her babies together and the girl I recieved reportedly ate one of her brothers.
Hope this helps.
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Steve
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