Can we load balance DNS server requests with other servers in Mikrotik? like in round robin style ?

In a way, yes. You could have one device (a load balancer; be it a MikroTik router or something more specialized for a load balancer) forward every Nth packet to one IP, while forwarding every (N+1)th packet to another.

However, since DNS is (mostly) a UDP protocol, i.e. it has only one request packet and one response packet, you won't really be able to handle much more load than if the load balancer itself is a DNS server.

I mean, the very process of checking the packet, forwarding it, and forwarding back the response packet is pretty much as taxing as a DNS query IF the name is already in the DNS' cache. Sure, forwarding is less taxing than a first time DNS lookup, but surely you'd use a DNS cache.

We use unbound with anycast and bgp