I decided to build my own mining farm...Can I order large of amount like 1000 in one time???
Yes, of course.
You only have to contact the manufacturers.
Do you know some manufacturers ?
No ?
Too bad.
Only one serious manufacturer is selling his products : Bitmain.
But Bitmain is also a miner and selling 1000 Antminer is probably not a so good business for it.
1000 Antminer is not at all damaging its own mining-business. It's like 0.2% of the total hashpower... That's such a small change, together with Bitmain actually gaining money from those antminers... It's pretty good for them.