Limit on how many neighbors

Hi, We are running Bird with OSPF between embedded routers (openwrt) (mobile routers). The routers are connected to our main server with openvpn, and we are using bird ontop on openvpn to deliver routes to the end routers. This have worked quite well, but today we notice some glitches. We had some routers that did not finish election (ie, stand in init instead of being full). When we count, there are exactly 100 devices that are in "full", and 3 in init. Are there any limit on how many neighbors/routers? Med vänlig hälsning / Best regards Magnus Löfqvist