Sorry to bother, but I think the experts can help me here, please.

I have to bitches, a 4 year old and a 8 year old, last days the older one thinks she is a male and is trying to breed with the little one, or humps over her and she starts moving like she is a male trying to breed.

I hope you all understand my english and my question.

Thank you,

The one bitch is trying to be dominant over the other one and that is how they show it. If one of the bitches is in heat they may also take turns 'humping' each other.

Or may be the old one will be in heath soon?, or doesn't have to do anything with this.

Having a house full of bitches I see it all the time. I see it especially when one is going into season, but sometimes its just establishing ranks within the pack. I hope this helps.

Yes, happens here also with all my bitches...

Not only when one or the other is coming into season, but sometimes it happens if one has a vaginal infection.

My pack here is well aware the spayed female is the alpha bitch (of course behind me-LOL), however when one of my intact girls is coming into heat, she will hump my spayed girl....at times I have had a congo line.